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  • 1.
    Andersson, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN studies, Luleå, Sweden..
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN studies, Luleå, Sweden.
    Nordberg, Gunnar
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagenbjörk, Annika
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN studies, Luleå, Sweden.
    Eriksson, Kåre
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN studies, Luleå, Sweden.
    Early life swimming pool exposure and asthma onset in children: a case-control study2018In: Environmental health, ISSN 1476-069X, E-ISSN 1476-069X, Vol. 17, article id 34Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Trichloramine exposure in indoor swimming pools has been suggested to cause asthma in children. We aimed to investigate the risk of asthma onset among children in relation to individual trichloramine exposure.

    METHODS: A longitudinal nested case-control study of 337 children with asthma (cases) and 633 controls aged 16-17 years was performed within a population-based cohort from The Obstructive Lung Disease in Northern Sweden studies (OLIN). Year of asthma onset and exposure time at different ages were obtained in telephone interviews. Trichloramine concentrations in the pool buildings were measured. Skin prick test results for inhalant allergens were available from previous examinations of the cohort. The risk for asthma was analyzed in relation to the cumulative trichloramine exposure before onset of asthma.

    RESULTS: Swimming pool exposure in early life was associated with a significantly higher risk of pre-school asthma onset. A dose-response relationship between swimming pool exposure and asthma was indicated in children with asthma onset at 1 year of age. Children who were both sensitized and exposed had a particularly high risk.

    CONCLUSIONS: Early life exposure to chlorinated swimming pool environments was associated with pre-school asthma onset.

  • 2.
    Andersson, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    The clinical expression of asthma in schoolchildren has changed between 1996 and 20062010In: Pediatric Allergy and Immunology, ISSN 0905-6157, E-ISSN 1399-3038, Vol. 21, no 5, p. 859-866Article in journal (Refereed)
    Abstract [en]

    Several studies have reported diverging trends in the prevalence of asthma and wheeze. The aim of this study was to investigate the clinical expression of childhood asthma in 1996 and 2006 by studying asthma morbidity, treatment, and environmental exposures in school children with physician-diagnosed asthma and wheeze, respectively. All children enrolled in first or second grade (7-8 yr-old) in three municipalities in northern Sweden were invited to a questionnaire study in 1996 and 2006, respectively. In 1996, 3430 (97%) participated; and in 2006, 2585 (96%) participated. The same parental completed questionnaire, including the ISAAC questions, was used in both surveys. Physician-diagnosed asthma was reported at 5.7% in 1996 and 7.4% in 2006. A significantly greater proportion of children with asthma were using inhaled corticosteroids (ICS) in 2006, 67% vs. 55% in 1996. This increase was parallel to a major decrease in severe asthma symptoms such as disturbed sleep because of wheeze (49% vs. 38%) and troublesome asthma (21% vs. 11%). The prevalence of current wheeze among the asthmatics decreased significantly; however, this was seen only among children not using ICS. Parental smoking decreased significantly as did the proportion living in damp buildings. In conclusion, although asthma remains a major public health issue in school age children, children with asthma had less respiratory symptoms and a better asthma control in 2006 compared to 1996. This parallels with an increase in treatment with ICS, more beneficial environmental conditions, and an increased diagnostic intensity resulting in a larger proportion of children with mild symptoms being diagnosed as having asthma.

  • 3.
    Andersson, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Luleå.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Luleå.
    Bjerg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. The OLIN Studies, Luleå ; Krefting Research Centre, Institute of Medicine, Göteborgs universitet.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundbäck, Bo
    The OLIN Studies, Luleå ; Krefting Research Centre, Institute of Medicine, Göteborgs universitet.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Luleå.
    Remission and Persistence of Asthma Followed From 7 to 19 Years of Age2013In: Pediatrics, ISSN 0031-4005, E-ISSN 1098-4275, Vol. 132, no 2, p. E435-E442Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND OBJECTIVE: To date, a limited number of population-based studies have prospectively evaluated the remission of childhood asthma. This work was intended to study the remission and persistence of childhood asthma and related factors. METHODS: In 1996, a questionnaire was distributed to the parents of all children aged 7 to 8 years in 3 municipalities in northern Sweden, and 3430 (97%) participated. After a validation study, 248 children were identified as having asthma; these children were reassessed annually until age 19 years when 205 (83%) remained. During the follow-up period lung function, bronchial challenge testing, and skin prick tests were performed. Remission was defined as no use of asthma medication and no wheeze during the past 12 months as reported at endpoint and in the 2 annual surveys preceding endpoint (ie, for >= 3 years). RESULTS: At age 19 years, 21% were in remission, 38% had periodic asthma, and 41% persistent asthma. Remission was more common among boys. Sensitization to furred animals and a more severe asthma (asthma score >= 2) at age 7 to 8 years were both inversely associated with remission, odds ratio 0.14 (95% confidence interval 0.04-0.55) and 0.19 (0.07-0.54), respectively. Among children with these 2 characteristics, 82% had persistent asthma during adolescence. Asthma heredity, damp housing, rural living, and smoking were not associated with remission. CONCLUSIONS: The probability of remission of childhood asthma from age 7- to 8-years to age 19 years was largely determined by sensitization status, particularly sensitization to animals, asthma severity, and female gender, factors all inversely related to remission.

  • 4.
    Andersson, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnéa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Lundbäck, B
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Persistence and remission of asthma followed from 7 to 19 years of ageManuscript (preprint) (Other academic)
  • 5.
    Andersson, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Norrbotten County Council, Luleå, Sweden.
    Hedman, Linnéa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Norrbotten County Council, Luleå, Sweden.
    Nordberg, Gunnar
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eriksson, Kåre
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Norrbotten County Council, Luleå, Sweden.
    Swimming pool attendance is related to asthma among atopic school children: a population-based study2015In: Environmental health, ISSN 1476-069X, E-ISSN 1476-069X, Vol. 14, no 14, article id 37Article in journal (Refereed)
    Abstract [en]

    Background: By-products of water disinfectants have been suggested to cause asthma, especially in atopic children. However, studies on indoor swimming pool attendance and asthma in children have presented conflicting results. The present study examined the relationship between indoor swimming pool attendance and asthma among sensitized and non-sensitized children aged 11-12 years.

    Methods: An extended ISAAC questionnaire was sent to the families of all children attending fifth or sixth grade, aged 11-12 years, in two municipalities in Northern Sweden in 2010. A total of 1866 participated (96% of those invited) in the questionnaire study and 1652 (89%) also participated in skin prick testing for 10 standard airborne allergens. Asthma was defined as physician-diagnosed asthma in combination with wheeze or use of asthma medication in the last 12 months. Current swimming pool attendance was reported as >= 1/week or <1/week. Logistic regression models were used for data analysis.

    Results: The prevalence of current asthma was 8.9% (10.0% of boys; 7.9% of girls) and 14% had attended indoor pools >= 1/week. Children currently attending swimming pools >= 1/week had an increased risk of current asthma. Stratified analyses for allergic sensitization adjusted for sex, parental smoking, parental asthma, and damp housing, showed a statistically significant association for current asthma only among sensitized subjects (OR 95% CI 1.90 1.09-3.32). No association was found between current pool attendance and wheeze, sensitization, rhinitis or eczema.

    Conclusions: The present study supports the proposed link between indoor swimming pool attendance and asthma in sensitized children.

  • 6.
    Andersson, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Modig, Lars
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Heavy vehicle traffic is related to wheeze among schoolchildren: a population-based study in an area with low traffic flows2011In: Environmental health, ISSN 1476-069X, E-ISSN 1476-069X, Vol. 10, no 91Article in journal (Refereed)
    Abstract [en]

    Background: An association between traffic air pollution and respiratory symptoms among children has been reported. However, the effects of traffic air pollution on asthma and wheeze have been very sparsely studied in areas with low traffic intensity in cold climate with poor dispersion. We evaluated the impact of vehicle traffic on childhood asthma and wheeze by objective exposure assessment.

    Methods: As a part of the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a questionnaire was sent to the families of all children attending first or second grade in Luleå (72,000 inhabitants) in Northern Sweden in 2006. The age of the children was 7-8 years and the participation rate was 98% (n = 1357). Skin prick tests were performed in 1224 (89%) children. The home addresses were given geographical coordinates and traffic counts were obtained from the local traffic authorities. A proximity model of average daily traffic and average daily heavy vehicle traffic within 200 meters from each participant's home address was used. The associations between traffic exposure and asthma and wheeze, respectively, were analysed in an adjusted multiple logistic regression model.

    Results: Exposure to high traffic flows was uncommon in the study area; only 15% of the children lived within 200 meters from a road with a traffic flow of ≥8000 vehicles per day. Living closer than 200 meters from a road with ≥500 heavy vehicles daily was associated with current wheeze, odds ratio 1.7 (confidence interval 1.0-2.7). A dose-response relation was indicated. An increased risk of asthma was also seen, however not significant, odds ratio 1.5 (confidence interval 0.8-2.9). Stratified analyses revealed that the effect of traffic exposure was restricted to the non-sensitized phenotype of asthma and wheeze. The agreement between self-reported traffic exposure and objective measurements of exposure was moderate.

    Conclusions: This study showed that already at low levels of exposure, vehicle traffic is related to an increased risk of wheeze among children. Thus, the global burden of traffic air pollution may be underestimated.

  • 7. Andersson, Mikael
    et al.
    Stridsman, Caroline
    Emtner, Margareta
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Physical activity and fatigue in chronic obstructive pulmonary disease - A population based study2015In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 109, no 8, p. 1048-1057Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: In subjects with chronic obstructive pulmonary disease (COPD), symptoms of fatigue, concomitant heart disease and low physical activity levels are more frequently described than in subjects without COPD. However, there are no population-based studies addressing the relationship between physical activity, fatigue and heart disease in COPD. The aim was to compare physical activity levels among subjects with and without COPD in a population based study, and to evaluate if concomitant heart disease and fatigue was associated to physical activity.

    METHODS: In this, 470 subjects with COPD and 659 subjects without COPD (non-COPD) participated in examinations including structured interview and spirometry. A ratio of the forced expiratory volume in one second (FEV1)/best of forced vital capacity (FVC) and vital capacity (VC) < 0.7 was used to define COPD. Physical activity was assessed with the International Physical Activity Questionnaire (IPAQ), and fatigue with the Functional Assessment of Chronic Illness Therapy - Fatigue scale (FACIT-F).

    RESULTS: The prevalence of low physical activity was higher among subjects with FEV1 < 80% predicted compared to non-COPD subjects (22.4% vs. 14.6%, p = 0.041). The factors most strongly associated with low physical activity in subjects with COPD were older age, OR 1.52, (95% CI 1.12-2.06), a history of heart disease, OR 2.11 (1.10-4.08), and clinically significant fatigue, OR 2.33 (1.31-4.13); while obesity was the only significant factor among non-COPD subjects, OR 2.26 (1.17-4.35).

    CONCLUSION: Physical activity levels are reduced when lung function is decreased below 80% of predicted, and the factors associated with low physical activity are different among subject with and without COPD. We propose that the presence of fatigue and heart disease are useful to evaluate when identifying subjects for pulmonary rehabilitation.

  • 8. Axelsson, Malin
    et al.
    Ekerljung, Linda
    Eriksson, Jonas
    Hagstad, Stig
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Research and Development, Obstructive Lung Disease In Northern Sweden (OLIN) Studies, Norrbotten County Council, Luleå.
    Lötvall, Jan
    Lundbäck, Bo
    Chronic bronchitis in West Sweden - a matter of smoking and social class2016In: European clinical respiratory journal, ISSN 2001-8525, Vol. 3, article id 30319Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Although chronic bronchitis is associated with impaired quality of life, hospitalisations and increased mortality, it has been less in focus after the introduction of the term chronic obstructive pulmonary disease (COPD). There are no recent published data on the prevalence of chronic bronchitis from the Scandinavian countries.

    AIM: The main aim of the present study was to estimate the prevalence of chronic bronchitis in West Sweden by using data from a large-scale epidemiological study of the general population. A further aim was to identify current risk factors for chronic bronchitis in a population with a major decrease in the proportion of smokers.

    METHODS: From the 18,087 questionnaire responders out of 30,000 invited to participate at the West Sweden Asthma Study, 2,000 subjects were randomly selected and invited to detailed clinical examinations performed during 2009-2013. A total of 1,172 subjects aged 17-79 participated in the examinations which included, among others, spirometry and structured interviews. Chronic bronchitis was defined according to reported symptoms.

    RESULTS: The overall prevalence of chronic bronchitis was 7.2% (men 7.6%; women 6.8% ns), and it was 8.7% in subjects older than age 60. Chronic bronchitis was strongly associated with smoking, defined both as current smoking status and pack-years. Other risk factors were increasing age, low socio-economic class and urban living. Of those with chronic bronchitis, 22% fulfilled the GOLD criteria of COPD.

    CONCLUSION: The prevalence of chronic bronchitis was somewhat lower than found by studies in Sweden in the 1980s and the prevalence was now similar in men and women. Although smoking was still the dominating risk factor for chronic bronchitis, the relative importance of smoking had decreased parallel with a decreasing smoking prevalence, while the relative importance of other factors than smoking had increased compared to previous studies.

  • 9. Axelsson, Malin
    et al.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Kainu, Annette
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Respiratory symptoms increase health care consumption and affect everyday life: a cross-sectional population-based study from Finland, Estonia, and Sweden2016In: European Clinical Respiratory Journal, ISSN 2001-8525, Vol. 3, article id 31024Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Even though respiratory symptoms are common in the adult population, there is limited research describing their impact on everyday life and association with health care consumption.

    AIM: The main objective of this population-based study was to estimate and compare the prevalence of respiratory symptoms among adults in Finland, Estonia, and Sweden in relation to health care consumption and to identify factors influencing health care consumption. A secondary aim was to assess to which extent the presence of respiratory symptoms affect everyday life.

    METHOD: In the population-based FinEsS studies consisting of random samples of subjects aged 20 to 69 years from Finland (n=1,337), Estonia (n=1,346), and Sweden (n=1,953), data on demographics, respiratory health, and health care consumption were collected by structured interviews. Prevalence was compared and multiple logistic regression analyses were performed.

    RESULTS: Respiratory symptoms were significantly more common in Finland (66.0%) and Estonia (65.2%) than in Sweden (54.1%). Among subjects with respiratory symptoms, the proportion reporting outpatient care during the past year was fairly similar in the three countries, while specialist consultations were more common in Finland (19.1%), and hospitalisations more common in Estonia (15.0%). Finnish and Estonian residency, female sex, and BMI>25 increased the risk for outpatient care consumption. Wheeze and attacks of shortness of breath in the past 12 months, recurrent sputum production, and cough were associated with an increased risk for health care consumption. Increasing number of respiratory symptoms increased the risk for consuming health care. A larger proportion of subjects in Estonia and Sweden experienced their everyday life being affected by respiratory symptoms compared with subjects in Finland.

    CONCLUSION: Respiratory symptoms are common in Finland, Estonia, and Sweden and contribute to a negative impact on everyday life as well as increased health care consumption. The observed differences in health care consumption between countries are probably related to national differences in health care structure.

  • 10.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Ekerljung, Linda
    Eriksson, Berne
    Stridsman, Caroline
    Mincheva, Roxana
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagstad, Stig
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ullman, Anders
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundback, Bo
    Decrease in prevalence of COPD in Sweden after decades of decrease in smoking2018In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 52Article in journal (Other academic)
    Abstract [en]

    Background: The smoking prevalence in Sweden has steadily decreased during three decades. The prevalence of COPD in Sweden in the 1990s and around the millennium shift was similar to neighboring European countries, i.e. estimated at 11-17%, and of moderate to severe COPD to 7-11%, in ages over 40y.

    Aim: Has the prevalence of chronic airway obstruction (CAO) and of COPD in Sweden decreased after decades of decreasing smoking prevalence?

    Methods: Within two large scale population studies in progress, the West Sweden Asthma Study (WSAS) and the Obstructive Lung Disease in Northern Sweden Studies (OLIN), the prevalence of COPD in ages 41-72y was calculated among randomly selected subjects from the general population in 2009-2012. The following post-bronchodilator definitions were used; CAO: FEV1/FVC<LLN and FEV1/FVC<0.7; moderate to severe CAO: FEV1/FVC<LLN with FEV1<LLN, and FEV1/FVC<0.7 with FEV1<80% of predicted. In line with the GOLD 2017 guidelines, both CAO and respiratory symptoms were required for the diagnosis of COPD.

    Results: The prevalence of CAO based on the FEV1/FVC<LLN and FEV1/FVC<0.7 criteria, respectively, was 6.4% and 10.3%, while the corresponding prevalence of COPD was 5.6% and 8.4%. The prevalence of moderate to severe CAO was 4.0% (LLN-criterion) and 5.0% (fixed ratio-criterion) and of moderate to severe COPD 3.8% and 4.4%, respectively. Main risk factors for both CAO and COPD were smoking, male sex and increasing age.

    Conclusion: As prevalence of COPD defined as chronic airway obstruction before and around the millennium shift was estimated at 11-17% in ages >40 years, the prevalence of COPD has decreased in Sweden, and the decrease in smoking over decades is probably the main causal factor.

  • 11.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eriksson, Berne
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Department of Health Sciences, Division of Nursing, Luleå University of Technology, Luleå, Sweden.
    Stridsman, Caroline
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sovijärvi, Anssi
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
    Restrictive spirometric pattern in the general adult population: methods of defining the condition and consequences on prevalence2016In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 120, p. 116-123Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Attempts have been made to use dynamic spirometry to define restrictive lung function, but the definition of a restrictive spirometric pattern (RSP) varies between studies such as BOLD and NHANES. The aim of this study was to estimate the prevalence and risk factors of RSP among adults in northern Sweden based on different definitions.

    METHODS: In 2008-2009 a general population sample aged 21-86y within the obstructive lung disease in northern Sweden (OLIN) studies was examined by structured interview and spirometry, and 726 subjects participated (71% of invited). The prevalence of RSP was calculated according to three different definitions based on pre-as well as post-bronchodilator spirometry: 1) FVC < 80% & FEV1/FVC > 0.7 2) FVC < 80% & FEV1/FVC > LLN 3) FVC < LLN & FEV1/FVC > LLN RESULTS: The three definitions yielded RSP prevalence estimates of 10.5%, 11.2% and 9.4% respectively, when based on pre-bronchodilator values. The prevalence was lower when based on post-bronchodilator values, i.e. 7.3%, 7.9% and 6.6%. According to definition 1 and 2, the RSP prevalence increased by age, but not according to definition 3. The overlap between the definitions was substantial. When corrected for confounding factors, manual work in industry and diabetes with obesity were independently associated with an increased risk for RSP regardless of definition.

    CONCLUSIONS: The prevalence of RSP was 7-11%. The prevalence estimates differed more depending on the choice of pre- compared to post-bronchodilator values than on the choice of RSP definition. RSP was, regardless of definition, independently associated with manual work in industry and diabetes with obesity.

  • 12.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eriksson, Berne
    Halmstad, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Stridsman, Caroline
    Luleå, Sweden.
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
    Decreased prevalence of moderate to severe COPD over 15 years in northern SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    Background: The burden of COPD in terms of mortality, morbidity, costs and prevalence has increased worldwide. Recent results on prevalence in Western Europe are conflicting. In Sweden smoking prevalence has steadily decreased over the past 30 years. 

    Aim: The aim was to study changes in prevalence and risk factor patterns of COPD in the same area and within the same age-span 15 years apart.

    Material and methods: Two population-based cross-sectional samples in ages 23-72 years participating at examinations in 1994 and 2009, respectively, were compared in terms of COPD prevalence, severity and risk factor patterns. Two different definitions of COPD were used; FEV1/FVC<LLN and FEV1/FVC<0.7. The severity of COPD was assessed by FEV1, both as % of predicted and in relation to the LLN.

    Results: The prevalence of COPD decreased significantly from 9.5% to 6.3% (p=0.030) according to the FEV1/FVC<LLN criterion, while the decrease based on the FEV1/FVC<0.7 criterion from 10.5% to 8.5% was non-significant. The prevalence of moderate to severe COPD decreased substantially and significantly, and the risk factor pattern was altered in 2009 when, beside age and smoking, also socio-economic status based on occupation was significantly associated with COPD. 

    Conclusions: Changes in both prevalence and risk factor patterns of COPD were observed between surveys. Following a continuing decrease in smoking habits over several decades, a decrease in the prevalence of moderate to severe COPD was observed from 1994 to 2009 in northern Sweden.

  • 13.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Unit, Umeå University, Umeå, Sweden..
    Eriksson, Berne
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Unit, Umeå University, Umeå, Sweden..
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Unit, Umeå University, Umeå, Sweden..
    Stridsman, Caroline
    Dept of Health Sciences, Luleå University, Luleå, Sweden..
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Unit, Umeå University, Umeå, Sweden..
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Unit, Umeå University, Umeå, Sweden; Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden..
    Decreased prevalence of moderate to severe COPD over 15 years in northern Sweden2016In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 114, p. 103-110Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The burden of COPD in terms of mortality, morbidity, costs and prevalence has increased worldwide. Recent results on prevalence in Western Europe are conflicting. In Sweden smoking prevalence has steadily decreased over the past 30 years.

    AIM: The aim was to study changes in prevalence and risk factor patterns of COPD in the same area and within the same age-span 15 years apart.

    MATERIAL AND METHODS: Two population-based cross-sectional samples in ages 23-72 years participating at examinations in 1994 and 2009, respectively, were compared in terms of COPD prevalence, severity and risk factor patterns. Two different definitions of COPD were used; FEV1/FVC < LLN and FEV1/FVC < 0.7. The severity of COPD was assessed by FEV1, both as % of predicted and in relation to the LLN.

    RESULTS: The prevalence of COPD decreased significantly from 9.5% to 6.3% (p = 0.030) according to the FEV1/FVC < LLN criterion, while the decrease based on the FEV1/FVC < 0.7 criterion from 10.5% to 8.5% was non-significant. The prevalence of moderate to severe COPD decreased substantially and significantly, and the risk factor pattern was altered in 2009 when, beside age and smoking, also socio-economic status based on occupation was significantly associated with COPD.

    CONCLUSIONS: Changes in both prevalence and risk factor patterns of COPD were observed between surveys. Following a continuing decrease in smoking habits over several decades, a decrease in the prevalence of moderate to severe COPD was observed from 1994 to 2009 in northern Sweden.

  • 14.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Department of Research and Development, Norrbotten County Council, Luleå.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Department of Research and Development, Norrbotten County Council, Luleå.
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Department of Research and Development, Norrbotten County Council, Luleå,.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. The OLIN Studies, Department of Research and Development, Norrbotten County Council, Luleå, Sweden.
    Lundbäck, Bo
    The OLIN Studies, Department of Research and Development, Norrbotten County Council, Luleå, Sweden ; Krefting Research Centre/Department of Internal Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Department of Research and Development, Norrbotten County Council, Luleå.
    Prevalence trends in respiratory symptoms and asthma in relation to smoking: two cross-sectional studies ten years apart among adults in northern Sweden2014In: The World Allergy Organization journal, ISSN 1939-4551, Vol. 7, no 1, p. 1-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Smoking is considered to be the single most important preventable risk factor for respiratory symptoms. Estimating prevalence of respiratory symptoms is important since they most often precede a diagnosis of an obstructive airway disease, which places a major burden on the society. The aim of this study was to estimate prevalence trends of respiratory symptoms and asthma among Swedish adults, in relation to smoking habits. A further aim was to estimate the proportion of respiratory symptom and asthma prevalence attributable to smoking.

    METHODS: Data from two large-scale cross-sectional surveys among adults performed in northern Sweden in 1996 and 2006 were analysed. Identical methods and the same questionnaire were used in both surveys. The association between smoking, respiratory symptoms and asthma was analysed with multiple logistic regression analyses. Changes in prevalence of respiratory symptoms and asthma from 1996 to 2006 were expressed as odds ratios. Additionally, the population attributable risks of smoking were estimated.

    RESULTS: The prevalence of most respiratory symptoms decreased significantly from 1996 to 2006. Longstanding cough decreased from 12.4 to 10.1%, sputum production from 19.0 to 15.0%, chronic productive cough from 7.3 to 6.2%, and recurrent wheeze from 13.4 to 12.0%. Any wheeze and asthmatic wheeze remained unchanged. This parallels to a decrease in smoking from 27.4 to 19.1%. In contrast, physician-diagnosed asthma increased from 9.4 to 11.6%. The patterns were similar after correction for confounders. All respiratory symptoms were highly associated with smoking, and the proportion of respiratory symptoms in the population attributed to smoking (PAR) ranged from 9.8 to 25.5%. In 2006, PAR of smoking was highest for recurrent wheeze (20.6%).

    CONCLUSIONS: In conclusion, we found that respiratory symptoms, in particular symptoms common in bronchitis, decreased among adults in northern Sweden, parallel to a decrease in smoking from 1996 to 2006. In contrast, the prevalence of physician-diagnosed asthma increased during the same time-period. Up to one fourth of the respiratory symptom prevalence in the population was attributable to smoking.

  • 15.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Department of Health Sciences, Luleå University, Luleå, Sweden.
    Stridsman, Caroline
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    A population-based cohort of adults with asthma: mortality and participation in a long-term follow-up2017In: European Clinical Respiratory Journal, ISSN 2001-8525, Vol. 4, article id 1334508Article in journal (Refereed)
    Abstract [en]

    Background and objective: Asthma is a major public health concern. The aim of this study was to characterize a large population-based cohort of adults with asthma, and to study factors associated with all-cause mortality and non-participation in a long-term follow-up. Design: Random and stratified samples from five population-based cohorts were clinically examined during 1986-2001, and all subjects with asthma were included in the study (n = 2055, age 19-72 years, 55% women). Independent associations between different risk factors and (i) mortality and (ii) non-participation in a clinical follow-up in 2012-2014 were estimated. Results: In 1986-2001, 95% reported any wheeze and/or attacks of shortness of breath in the past 12 months, and/or asthma medication use. Over the up to 28 years of follow-up time, the cumulative mortality was 22.7%. Male gender, current smoking, and lower forced expiratory volume in 1 sec of predicted (FEV1% of predicted) were independent risk factors for mortality, while obesity was associated with non-participation in the follow-up. Older ages, ischemic heart disease, and low socioeconomic status were associated with both mortality and non-participation. Conclusions: The risk factors associated with mortality in this adult population-based asthma cohort were similar to those commonly identified in general population samples, i.e. male gender, current smoking, and lower FEV1% of predicted, while obesity was associated with non-participation in a long-term follow-up. Ischemic heart disease, low socioeconomic status, and older ages were associated with both mortality and non-participation.

  • 16.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Stridsman, Caroline
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundback, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eosinophilic inflammation and lung function decline in a long-term follow-up of a large population-based asthma cohort2018In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 52Article in journal (Other academic)
    Abstract [en]

    The relationship between lung function decline and airway inflammation among asthmatics has important therapeutic implications, but has rarely been studied in large samples or in population-based asthma cohorts.

    A population-based adult asthma cohort (n=2055) was recruited during 1986-2001 and clinically examined including spirometry. In 2012-2014, all still eligible subjects (n=1425) were invited to a clinical follow-up including spirometry, blood sampling, and a structured interview, and n=1006 participated (55% women, mean age 59y, 32-92y). Linear regression was performed with age, sex, smoking habits, year of first examination, family history of asthma, socioeconomic status, eosinophils (EOS)>=0.3x109/L, and neutrophils (NEUT)>=5.0x109/L as independent variables and pre-bronchodilator FEV1 decline/year (ml and % of predicted [pp], respectively) as dependent. In secondary models, both ICS use at baseline and ICS use at follow-up were also included.

    The mean annual FEV1 decline in ml (pp) among asthmatics with EOS<0.3, 0.4>EOS>=0.3 and EOS>=0.4x109/L, respectively, was 26ml (0.03pp), 29ml (0.10pp) and 34ml (0.27pp) (p<0.001). In adjusted analyses, EOS>=0.3 was significantly associated with FEV1 decline, both in terms of ml (4ml excess annual decline vs EOS<0.3) and pp. The association between EOS and FEV1 decline in pp, but not ml, remained when additionally adjusted for ICS use. The association with NEUT>=5.0x109/L was less clear.

    On group level, adult asthmatics with higher levels of eosinophils in blood have a history of excess FEV1 decline compared to asthmatics with lower levels of eosinophil inflammation, independent of other factors such as ICS use.

  • 17.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Stridsman, Caroline
    Eriksson, Berne
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eklund, Britt-Marie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundback, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Severe asthma among adults: Prevalence and clinical characteristics2018In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 52Article in journal (Other academic)
    Abstract [en]

    Background: Severe asthma is a considerable challenge for patients, health care professionals and society. Few studies have estimated the prevalence of severe asthma according to modern definitions of which none based on a population study.

    Methods: We estimated the prevalence and studied characteristics of severe asthma in a large adult population-based asthma cohort followed for 10-28 years in northern Sweden: 1006 subjects participated in a follow-up during 2012-14, when 830 (82.5%) still had current asthma (mean age 59y, 32-92y, 56% women). Severe asthma was defined according to three internationally well-known criteria: the US SARP, ATS/ERS and GINA. All subjects with severe asthma were undergoing respiratory specialist care, and were also contacted by telephone to verify adherence to treatment.

    Results: The prevalence of severe asthma according to the three definitions was 3.6% (US SARP), 4.8% (ERS/ATS), and 6.1% (GINA) among subjects with current asthma. Although all were using high ICS doses and other maintenance treatment, >40% had uncontrolled asthma and <10% had controlled asthma according to the ACT. Severe asthma was related to age >50 years, nasal polyposis, decreased FEV1, not fully reversible airway obstruction, sensitization to aspergillus, elevated neutrophils and partly to eosinophils, and tended to be more common in women.

    Conclusion: The prevalence of severe asthma in this asthma cohort was 4-6%, corresponding to approximately 0.5% of the population in northern Sweden. A substantial proportion of those with severe asthma had uncontrolled disease, and severe asthma differed significantly from other asthma in terms of both clinical and inflammatory characteristics.

  • 18.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Stridsman, Caroline
    Eriksson, Berne
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Eklund, Britt-Marie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health. Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Severe asthma: A population study perspective2019In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 49, no 6, p. 819-828Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Severe asthma is a considerable challenge for patients, health care professionals and society. Few studies have estimated the prevalence of severe asthma according to modern definitions of which none based on a population study.

    OBJECTIVE: To describe characteristics and estimate the prevalence of severe asthma in a large adult population-based asthma cohort followed for 10-28 years.

    METHODS: N=1006 subjects with asthma participated in a follow-up during 2012-14, when 830 (mean age 59y, 56% women) still had current asthma. Severe asthma was defined according to three internationally well-known criteria: the ATS workshop definition from 2000 used in the US Severe Asthma Research Program (SARP), the 2014 ATS/ERS Task force definition and the GINA 2017. All subjects with severe asthma according to any of these criteria were undergoing respiratory specialist care, and were also contacted by telephone to verify treatment adherence.

    RESULTS: The prevalence of severe asthma according to the three definitions was 3.6% (US SARP), 4.8% (ERS/ATS Taskforce), and 6.1% (GINA) among subjects with current asthma. Although all were using high ICS doses and other maintenance treatment, >40% had uncontrolled asthma according to the asthma control test. Severe asthma was related to age >50 years, nasal polyposis, impaired lung function, sensitization to aspergillus, and tended to be more common in women. Further, neutrophils in blood significantly discriminated severe asthma from other asthma.

    CONCLUSIONS AND CLINICAL RELEVANCE: Severe asthma differed significantly from other asthma in terms of demographic, clinical and inflammatory characteristics, results suggesting possibilities for improved treatment regimens of severe asthma. The prevalence of severe asthma in this asthma cohort was 4-6%, corresponding to approximately 0.5% of the general population.

  • 19.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Stridsman, Caroline
    Department of Health Sciences, Luleå University, Luleå, Sweden.
    Muellerova, Hana
    Real-World Evidence&Epidemiology, GSK R&D, Uxbridge, UK.
    Wurst, Keele
    Real-World Evidence&Epidemiology, GSK R&D, Uxbridge, UK.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Department of Health Sciences, Luleå University, Luleå, Sweden.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Chronic airway obstruction in a population-based adult asthma cohort: Prevalence, incidence and prognostic factors2018In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 138, p. 115-122Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Asthma and COPD may overlap (ACO) but information about incidence and risk factors are lacking. This study aimed to estimate prevalence, incidence and risk factors of chronic airway obstruction (CAO) in a population-based adult asthma cohort.

    METHODS: /FVC<0.7.

    RESULTS: decline and higher levels of neutrophils than asthma only. Smoking, older age and male sex were independently associated with increased risk for both prevalent and incident CAO, while obesity had a protective effect.

    CONCLUSIONS: In this prospective adult asthma cohort, the majority did not develop CAO. Smoking, older age and male sex were risk factors for prevalent and incident CAO, similar to risk factors described for COPD in the general population.

  • 20.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Oden, Anders
    Ekerljung, Linda
    Hedman, Linnéa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Kainu, Annette
    Sovijärvi, Anssi
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Reference values for spirometry - report from the Obstructive Lung Disease in Northern Sweden studies2015In: European Clinical Respiratory Journal, ISSN 2001-8525, Vol. 2, article id 26375Article in journal (Refereed)
    Abstract [en]

    Background: Abnormal lung function is commonly identified by comparing observed spirometric values to corresponding reference values. It is recommended that such reference values for spirometry are evaluated and updated frequently. The aim of this study was to estimate new reference values for Swedish adults by fitting a multivariable regression model to a healthy non-smoking general population sample from northern Sweden. Further aims were to evaluate the external validity of the obtained reference values on a contemporary sample from south-western Sweden, and to compare them to the Global Lung Function Initiative (GLI) reference values.

    Method: Sex-specific multivariable linear regression models were fitted to the spirometric data of n=501 healthy non-smoking adults aged 22–91 years, with age and height as predictors. The models were extended to allow the scatter around the outcome variable to depend on age, and age-dependent spline functions were incorporated into the models to provide a smooth fit over the entire age range. Mean values and lower limits of normal, defined as the lower 5th percentiles, were derived.

    Result: This modelling approach resulted in unbiased estimates of the spirometric outcomes, and the obtained estimates were appropriate not only for the northern Sweden sample but also for the south-western Sweden sample. On average, the GLI reference values for forced expiratory volume in one second (FEV1) and, in particular, forced expiratory vital capacity (FVC) were lower than both the observed values and the new reference values, but higher for the FEV1/FVC ratio.

    Conclusion: The evaluation based on the sample of healthy non-smokers from northern Sweden show that the Obstructive Lung Disease in Northern Sweden reference values are valid. Furthermore, the evaluation based on the south-western Sweden sample indicates a high external validity. The comparison with GLI brought further evidence to the consensus that, when available, appropriate local population-specific reference values may be preferred.

  • 21.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sovijarvi, Anssi
    Larsson, Kjell
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Evaluation of the global lung function initiative 2012 reference values for spirometry in a Swedish population sample2015In: BMC Pulmonary Medicine, ISSN 1471-2466, E-ISSN 1471-2466, Vol. 15, article id 26Article in journal (Refereed)
    Abstract [en]

    Background: The Global Lung Function Initiative 2012 (GLI) reference values are currently endorsed by several respiratory societies but evaluations of applicability for adults resident in European countries are lacking. The aim of this study was to evaluate if the GLI reference values are appropriate for an adult Caucasian Swedish population.

    Methods: During 2008-2013, clinical examinations including spirometry were performed on general population samples in northern Sweden, in which 501 healthy Caucasian non-smokers were identified. Predicted GLI reference values and Z-scores were calculated for each healthy non-smoking subject and the distributions and mean values for FEV1, FVC and the FEV1/FVC ratio were examined. The prevalence of airway obstruction among these healthy non-smokers was calculated based on the Lower Limit of normal (LLN) criterion (lower fifth percentile) for the FEV1/FVC ratio. Thus, by definition, a prevalence of 5% was expected.

    Results: The Z-scores for FEV1, FVC and FEV1/FVC were reasonably, although not perfectly, normally distributed, but not centred on zero. Both predicted FEV1 and, in particular, FVC were lower compared to the observed values in the sample. The deviations were greater among women compared to men. The prevalence of airway obstruction based on the LLN criterion for the FEV1/FVC ratio was 9.4% among women and 2.7% among men.

    Conclusions: The use of the GLI reference values may produce biased prevalence estimates of airway obstruction in Sweden, especially among women. These results demonstrate the importance of validating the GLI reference values in different countries.

  • 22.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Räisänen, Petri
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Department of Health Sciences, Luleå University, Luleå, Sweden.
    Stridsman, Caroline
    Department of Health Sciences, Luleå University, Luleå, Sweden.
    Andersson, Martin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundbäck, Bo
    Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Increased prevalence of allergic asthma from 1996 to 2006 and further to 2016: results from three population surveys2017In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 47, no 11, p. 1426-1435Article in journal (Refereed)
    Abstract [en]

    Background: During the latter half of the 20th century, the prevalence of asthma and many other allergic diseases has increased. Information on asthma prevalence trends among adults after 2010, especially regarding studies separating allergic asthma from non-allergic asthma, is lacking.

    Objective: The aim was to estimate prevalence trends of current asthma among adults, both allergic and non-allergic, from 1996 to 2016.

    Methods: Three cross-sectional samples from the same area of Sweden, 20-69 years, participated in surveys with the same questionnaire in 1996 (n=7104 participants, 85% response rate), 2006 (n=6165, 77%) and 2016 (n=5466, 53%), respectively. Allergic rhino-conjunctivitis (ARC) was used as a marker for allergic sensitization to define allergic asthma.

    Results: The prevalence of current asthma increased from 8.4% (95% CI: 7.8-9.0) in 1996 to 9.9% (95% CI: 9.2-10.6) in 2006 and 10.9% (95% CI: 10.1-11.7) in 2016 (P<.001). Allergic asthma increased from 5.0% (95% CI: 4.5-5.5) in 1996 to 6.0% (95% CI: 5.4-6.6) in 2006 and further to 7.3% (95% CI: 6.6-8.0) in 2016 (P<.001), while the prevalence of non-allergic asthma remained stable around 3.4%-3.8%. The increase in current asthma was most pronounced among women and among the middle-aged. Physician-diagnosed asthma, asthma medication use and ARC also increased significantly, while the prevalence of symptoms common in asthma such as wheeze and attacks of shortness of breath decreased slightly or was stable. The prevalence of current smoking decreased from 27.4% in 1996 to 12.3% in 2016.

    Conclusions and clinical relevance: The prevalence of allergic asthma increased from 1996 to 2006 and further to 2016, while the prevalence of non-allergic asthma remained on a stable prevalence level. The prevalence of symptoms common in asthma decreased slightly or was stable despite a substantial decrease in the prevalence of current smoking. Clinicians should be aware that the previously observed increase in prevalence of allergic asthma is still ongoing.

  • 23. Bakke, PS
    et al.
    Rönnmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eagan, T
    Pistelli, F
    Annesi-Maesano, I
    Maly, M
    Meren, M
    Vermeire, P
    Vestbo, J
    Viegi, G
    Zielinski, J
    Lundbäck, B
    Recommendations for epidemiological studies on COPD2011In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 38, no 6, p. 1261-1277Article in journal (Refereed)
    Abstract [en]

    The prevalence of chronic obstructive pulmonary disease (COPD) has been extensively studied, especially in Western Europe and North America. Few of these data are directly comparable because of differences between the surveys regarding composition of study populations, diagnostic criteria of the disease and definitions of the risk factors. Few community studies have examined phenotypes of COPD and included other ways of characterising the disease beyond that of spirometry. The objective of the present Task Force report is to present recommendations for the performance of general population studies in COPD in order to facilitate comparable and valid estimates on COPD prevalence by various risk factors. Diagnostic criteria in epidemiological settings, and standardised methods to examine the disease and its potential risk factors are discussed. The paper also offers practical advice for planning and performing an epidemiological study on COPD. The main message of the paper is that thorough planning is worth half the study. It is crucial to stick to standardised methods and good quality control during sampling. We recommend collecting biological markers, depending on the specific objectives of the study. Finally, studies of COPD in the population at large should assess various phenotypes of the disease.

  • 24. Berthold, Malin
    et al.
    Bjerg, Anders
    Winberg, Anna
    Mattsson, Lars
    Borres, Magnus
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine. Obstructive Lung Disease in Northern Sweden (OLIN) studies, Norrbotten county council, Luleå, Sweden.
    Association of Sensitization to Specific Pet Allergen Components with Asthma Symptoms in School Children2015In: Journal of Allergy and Clinical Immunology, ISSN 0091-6749, E-ISSN 1097-6825, Vol. 135, no 2, p. AB22-AB22Article in journal (Other academic)
    Abstract [en]

    Animal sensitization is a known determinant of asthma in children. The objective was to study the association of asthma with sensitization to pet allergen components in schoolchildren. Methods: A random sample of 696 children (11-12 y) from a Swedish population-based cohort was analyzed for sensitization (≥0.1 kUA/L) to cat, dog and horse dander extracts using ImmunoCAP. Sensitized children were further analyzed for IgE antibodies to animal allergen components using ImmunoCAP ISAC112. An expanded ISAAC questionnaire was completed by the parents. Results: Of 259 animal-sensitized children (37%) the majority (75%) were sensitized to more than one species. Among the 11 % (n=77) with current asthma 69 % were sensitized to at least one animal extract, as compared to one third of children without current asthma (p<0.001). Current asthma and asthma symptoms upon contact with cats were associated with co-sensitization to Fel d 1 and Fel d 4. Already at moderate levels of IgE antibodies to Fel d 4 (1-15 ISU), at which level most children were sensitized also to Fel d 1, the prevalence of asthma symptoms upon contact with cats was significantly increased. Dog-sensitized children were commonly sensitized to several dog components, and the greatest risk for asthma was seen in children co-sensitized to Can f 5 and Can f 1/f 2. Conclusions: Among Northern Swedish schoolchildren furry animals were the main perennial sensitizers. Asthma symptoms were associated with sensitizations to multiple components within an animal species. In particular, cat Fel d 4 sensitization was strongly related to asthma symptoms.

  • 25. Bjerg, A.
    et al.
    Winberg, Anna
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Johansson, R.
    Berthold, M.
    Borres, M.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Norrbotten City Council, OLIN Studies, Luleå, Sweden.
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Norrbotten City Council, OLIN Studies, Luleå, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Norrbotten City Council, OLIN Studies, Luleå, Sweden.
    Sensitization to animal allergen components in relation to asthma among young adults in Northern Sweden2019In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 74, p. 291-291Article in journal (Other academic)
  • 26. Bjerg, Anders
    et al.
    Ekerljung, Linda
    Eriksson, Jonas
    Näslund, Jonas
    Sjölander, Sigrid
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, Gothenburg University, Göteborg.
    Dahl, Åslög
    Holmberg, Kenneth
    Wennergren, Göran
    Torén, Kjell
    Borres, Magnus P
    Lötvall, Jan
    Lundbäck, Bo
    Increase in pollen sensitization in Swedish adults and protective effect of keeping animals in childhood2016In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 46, no 10, p. 1328-1336Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: To date, most studies of the "allergy epidemic" have been based on self-reported data. There is still limited knowledge on time trends in allergic sensitization, especially among adults.

    OBJECTIVE: To study allergic sensitization, its risk factors, and time trends in prevalence.

    METHODS: Within West Sweden Asthma Study (WSAS) a population-based sample of 788 adults (17-60y) underwent skin prick tests (SPT) for 11 aeroallergens 2009-2012. Specific IgE was analyzed in 750 of the participants. Those aged 20-46y (n=379) were compared with the European Community Respiratory Health Survey sample aged 20-46y from the same area (n=591) in 1991-1992.

    RESULTS: Among those aged 20-46y the prevalence of positive SPT to pollen increased; timothy from 17.1% to 29.0% (p<0.001) and birch from 15.6% to 23.7% (p=0.002) between 1991-1992 and 2009-2012. Measurements of specific IgE confirmed these increases. Prevalence of sensitization to all other tested allergens was unchanged. In the full WSAS sample aged 17-60y any positive SPT was seen in 41.9%, and the dominating sensitizers were pollen (34.3%), animals (22.8%) and mites (12.6%). Pollen sensitization was strongly associated with rhinitis, whereas indoor allergens were more associated with asthma. Growing up with livestock or furred pets decreased the risk of sensitization, adjusted odds ratio 0.53 (0.28-0.995) and 0.68 (0.47-0.98) respectively.

    CONCLUSION: Pollen sensitization has increased in Swedish adults since the early 1990's, while the prevalence of sensitization to other allergens has remained unchanged. This is one plausible explanation for the increase in rhinitis 1990-2008 in Swedish adults, during which time the prevalence of asthma, which is more associated with perennial allergens, was stable. Contact with animals in childhood seems to reduce the risk of sensitization well into adulthood. One major factor contributing to the rise in pollen allergy is a significant increase in levels of birch and grass pollen over the past three decades.

  • 27. Bjerg, Anders
    et al.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Perzanowski, Matthew
    Lundback, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    A Strong Synergism of Low Birth Weight and Prenatal Smoking on Asthma in Schoolchildren2011In: Pediatrics, ISSN 0031-4005, E-ISSN 1098-4275, Vol. 127, no 4, p. E905-E912Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Prenatal smoke exposure is associated with airway inflammation and asthma in children. It also increases the risk of low birth weight (LBW). LBW is associated with decreased lung function independently of smoking.

    OBJECTIVE: To study the independent and joint effects of prenatal smoking and LBW on childhood asthma.

    METHODS: In 1996, all children aged 7 to 8 years in 3 cities in northern Sweden were invited to an International Study of Asthma and Allergy in Childhood questionnaire survey. This study focused on the follow-up of children aged 11 to 12 years, in which 3389 children (96%) participated. A subset of 2121 children underwent skin-prick testing. Self-reported physician-diagnosed asthma has been clinically validated.

    RESULTS: Mean birth weight was 3360 g in children exposed to prenatal smoking and 3571 g in nonexposed children (P < .001). The association of prenatal smoking with physician-diagnosed asthma was stronger in LBW children (risk ratio: 8.8 [95% confidence interval: 2.1-38]) than in normal birth weight children (risk ratio: 1.3 [95% confidence interval: 1.0-1.8]). LBW alone was not an independent predictor of asthma. These associations were similar in multivariate analysis, and the interaction term LBW x smoking was highly statistically significant.

    CONCLUSIONS: There was a strong interaction of LBW and prenatal-smoking on the risk of physician-diagnosed asthma, which has not been demonstrated previously. This was consistently seen with adjustment for known risk factors, including allergic sensitization. Plausibly, airway inflammation from prenatal smoke exposure induces obstructive symptoms more easily in the underdeveloped airways of LBW children.

  • 28.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Perzanowski, Matthew S
    Platts-Mills, Thomas
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Family history of asthma and atopy: in-depth analyses of the impact on asthma and wheeze in 7- to 8-year-old children.2007In: Pediatrics, ISSN 1098-4275, Vol. 120, no 4, p. 741-8Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Development of asthma in children is influenced by interactions between genetic and environmental factors. It is unclear whether paternal or maternal histories of disease confer different risks. Previous population-based studies have not stratified analyses by child gender and sensitization status. Our aim was to study in detail the hereditary component of childhood asthma. METHODS: A population-based cohort of 3430 (97% of invited) 7- to 8-year-old school children participated in an expanded International Study of Asthma and Allergy in Childhood survey, and two thirds were skin-prick tested. Heredity was defined as a family history of (1) asthma and (2) atopy (allergic rhinitis or eczema). Multivariate analyses corrected for known risk factors for asthma. RESULTS: At ages 7 to 8, prevalence of asthma was 5.3% among the children and 9.0% among the parents. In children without parental asthma or parental atopy, the prevalence of asthma was 2.8%. Corrected for parental asthma, parental atopy was a weak but significant risk factor. There were minor differences in the impact of parental disease between sensitized and nonsensitized children and between boys and girls. CONCLUSIONS: As risk factors for childhood asthma, there were major differences between parental asthma and parental atopy. Sibling asthma was only a marker of parental disease. Interactions between parental disease and the child's allergic sensitization or gender were not statistically significant. Asthma in both parents conferred a multiplicative risk, whereas the effect of parental atopy was additive, however limited. Asthma and atopy, despite their causal relationship, are separate entities and could be inherited differently. This large, population-based, and well-characterized cohort study does not confirm parent-of-origin effects found in previous studies.

  • 29.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnéa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Perzanowski, Matthew
    Wennergren, Göran
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Decreased importance of environmental risk factors for childhood asthma from 1996 to 20062015In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 45, no 1, p. 146-153Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The large increase in asthma prevalence continues in several, but not all areas. Despite the individual risk factors that have been identified, the reasons for the observed trends in prevalence are largely unknown.

    OBJECTIVE: This study sought to characterize what trends in risk factors accompanied trends in asthma prevalence.

    METHODS: Two population-based cohorts of 7-8-year-old children from the same Swedish study areas examined by expanded ISAAC questionnaires were compared 10 years apart. In 1996 3,430 (97% participation) and in 2006 2,585 (96% participation) questionnaires were completed. A subset was skin-prick tested: in 1996, 2,148 (88% participation) and in 2006, 1,700 (90% participation) children. The adjusted population attributable fraction (aPAF) was calculated using the prevalence and multivariate odds ratio of each risk factor.

    RESULTS: The prevalence of current asthma and wheeze were similar in 1996 and 2006. Allergic sensitisation however increased from 21% to 30%. The prevalence of parental asthma increased from 17% to 24% while respiratory infections and maternal smoking decreased (60% to 29% and 32% to 16%, respectively). The aPAFs of non-environmental risk factors for current asthma increased 1996-2006: Allergic sensitization from 35% to 41%, parental asthma from 27% to 45% and male sex from 20% to 25%. Conversely, the aPAFs of environmental risk factors decreased: Respiratory infections from 36% to 32% and damp home and maternal smoking from 14% and 19% respectively to near zero in 2006.

    CONCLUSIONS AND CLINICAL RELEVANCE: From 1996 to 2006 the non-environmental risk factors parental asthma, allergic sensitisation and male sex had an increasing or constant importance for current asthma in 7-8-year-old children. The importance of the environmental exposures damp home, respiratory infections and maternal smoking decreased. This counter-balancing in risk factors may explain the level prevalence of current asthma.

  • 30.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Asthma in school age: prevalence and risk factors by time and by age2008In: Clinical Respiratory Journal, ISSN 1752-6981, E-ISSN 1752-699X, Vol. 2, no Suppl 1, p. 123-126Article in journal (Refereed)
    Abstract [en]

    Background: Childhood is the most important age for asthma development. Recent reports indicate that the prevalence of asthma. in children has plateaued after having increased for decades.

    Aims: To study prevalence and risk factor patterns of asthma by age and by time.

    Methods: In 1996, all children in grade 1-2 (age 7-8) in three cities ill Northern Sweden were invited to an expanded International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. A total of 3430 children (97%) participated yearly until 2000 (age 11-12). A subset (n = 2454) was invited to skill-prick testing in 1996 and 2000 with 88% and 90% participation. In 2006, another cohort (n = 2704) was identified and studied by identical methods with 96% participation. A total of 1700 children (90% of invited) were skin-prick tested.

    Results and comments: From age 7-8 to 11-12, the prevalence of physician-diagnosed asthma increased, 5.7%-7.7% (P<0.01) while current wheeze decreased, 11.7%-9.4% (P < 0.01), indicating a less diverse spectrum of symptoms with age. The yearly remission from asthma was 10% (lasting remission 5%), largely determined by allergic sensitisation. Allergic sensitisation (OR 5) and a family history of asthma (OR 3) were important risk factors for asthma at age 7-8 and 11-12. However, several other significant risk factors at age 7-8 (low birth weight, respiratory infections and house dampness) lost importance until age 11-12. Maternal and paternal asthma were equally important risk factors (OR 3-4) at age 7-8. Sibling asthma was only a marker of parental disease.

    Future perspectives: Through comparison with the 2006 cohort, trends in prevalence and in risk factors from 1996 to 2006 will be studied.

  • 31.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Lundbäck, B
    Rönnmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Time trends in asthma and wheeze in Swedish children 1996-2006: prevalence and risk factors by sex2010In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 65, no 1, p. 48-55Article in journal (Refereed)
    Abstract [en]

    Background: Recent data suggest that the previously rising trend in childhood wheezing symptoms has plateaued in some regions. We sought to investigate sex-specific trends in wheeze, asthma, allergic conditions, allergic sensitization and risk factors for wheeze.

    Methods: We compared two population-based cohorts of 7 to 8-year olds from the same Swedish towns in 1996 and 2006 using parental expanded ISAAC questionnaires. In 1996, 3430 (97%) and in 2006, 2585 (96%) questionnaires were completed. A subset was skin prick tested: in 1996, 2148 (88%) and in 2006, 1700 (90%) children participated.

    Results: No significant change in the prevalence of current wheeze (P = 0.13), allergic rhinitis (P = 0.18) or eczema (P = 0.22) was found despite an increase in allergic sensitization (20.6-29.9%, P < 0.01). In boys, however, the prevalence of current wheeze (12.9-16.4%, P < 0.01), physician-diagnosed asthma (7.1-9.3%, P = 0.03) and asthma medication use increased. In girls the prevalence of current symptoms and conditions tended to decrease. The prevalence of all studied risk factors for wheeze and asthma increased in boys relative to girls from 1996 to 2006, thus increasing the boy-to-girl prevalence ratio in risk factors.

    Conclusions: The previously reported increase in current wheezing indices has plateaued in Sweden. Due to increased diagnostic activity, physician diagnoses continue to increase. Time trends in wheezing symptoms differed between boys and girls, and current wheeze increased in boys. This was seemingly explained by the observed increases in the prevalence of risk factors for asthma in boys compared with girls. In contrast to the current symptoms of wheeze, rhinitis or eczema, the prevalence of allergic sensitization increased considerably.

  • 32.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, University of Gothenburg, Göteborg, Sweden.
    Winberg, Anna
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Berthold, Malin
    Mattsson, Lars
    Borres, Magnus P
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, University of Gothenburg, Göteborg, Sweden.
    A population-based study of animal component sensitization, asthma, and rhinitis in schoolchildren2015In: Pediatric Allergy and Immunology, ISSN 0905-6157, E-ISSN 1399-3038, Vol. 26, no 6, p. 557-563Article in journal (Refereed)
    Abstract [en]

    Background: Animal sensitization is a major determinant of asthma in children. Component-resolved studies of unselected pediatric populations are lacking. The aim was to describe sensitization to animal components and the association with asthma and rhinitis in animal-sensitized schoolchildren. Methods: A random sample of 696 children (11-12years) from a Swedish population-based cohort was tested for sensitization to cat, dog, and horse dander using ImmunoCAP. Sera from animal-sensitized children were further analyzed by microarray including three allergen components from cat, four from dog, and two from horse. The parents completed an expanded ISAAC questionnaire. Results: Of 259 animal-sensitized children (0.1 kU(A)/l), 51% were sensitized to all three, 23% to two, and 25% to one species. Current asthma and asthma symptoms following contact with cats were associated with co-sensitization to Fel d 1 and Fel d 4. This association was seen already at moderate-level sensitization (1-15 ISU) to Fel d 4, at which level most children were sensitized to Fel d 1, as well. In dog-sensitized children, the majority was sensitized to more than one dog component, and co-sensitization to Can f 5 and Can f 1/f 2 conferred the greatest risk for asthma. Sensitization to the highly cross-reactive serum albumins was uncommon and not associated with asthma. Conclusions: Among schoolchildren in northern Sweden, where mite allergy is uncommon, furry animals were the primary perennial sensitizers. Asthma was associated with higher levels of component sensitization, and sensitization to more than one component from the same animal conferred the greatest risk.

  • 33.
    Bjerg Bäcklund, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Perzanowski, M S
    Platts-Mills, T
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Asthma during the primary school ages--prevalence, remission and the impact of allergic sensitization.2006In: Allergy, ISSN 0105-4538, Vol. 61, no 5, p. 549-55Article in journal (Refereed)
  • 34.
    Bunne, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Moberg, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Department of Health Sciences, Division of Nursing, Luleå University of Technology, Luleå, Sweden.
    Andersson, Martin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Increase in allergic sensitization in schoolchildren: two cohorts compared 10 years apart2017In: Journal of Allergy and Clinical Immunology: In Practice, ISSN 2213-2198, E-ISSN 2213-2201, Vol. 5, no 2, p. 457-463Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Time trends of incidence of allergic sensitization are unknown and recent trends of prevalence and risk factors are lacking.

    OBJECTIVE: To estimate the incidence, prevalence, remission, risk factors, and time trends for allergic sensitization among schoolchildren followed from age 7 to 8 years to age 11 to 12 years.

    METHODS: In 2006, all children in grades 1 and 2 aged 7 to 8 years in 2 municipalities in northern Sweden were invited to a questionnaire survey and to skin prick testing to 10 common airborne allergens. The cohort was reexamined in 2010, with additional blood sampling for specific IgE. Participation rates were 90% (n = 1700) at age 7 to 8 years and 85% (n = 1657) at age 11 to 12 years. The results were compared with a cohort examined by identical methods 10 years earlier.

    RESULTS: The prevalence of positive skin prick test result to any allergen increased from 30% at age 7 to 8 years to 41% at age 11 to 12 years (P < .001). The cumulative 4-year incidence was 18%, while remission was low. Sensitization to pollen and furred animals was most common. A family history of allergy was significantly associated with incident sensitization, whereas the presence of furred animals at home was negatively associated. The prevalence at age 7 to 8 years and at age 11 to 12 years and the 4-year incidence were all significantly higher compared with the cohort examined 10 years earlier.

    CONCLUSIONS: The prevalence of allergic sensitization increased by age as a consequence of a high incidence and a low remission. The trends of increasing incidence and prevalence among schoolchildren imply future increases in the prevalence of allergic diseases.

  • 35. Commins, Scott P.
    et al.
    James, Hayley R.
    Kelly, Libby A.
    Pochan, Shawna L.
    Workman, Lisa J.
    Perzanowski, Matthew S.
    Kocan, Katherine M.
    Fahy, John V.
    Nganga, Lucy W.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Cooper, Philip J.
    Platts-Mills, Thomas A. E.
    The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose-alpha-1,3-galactose2011In: Journal of Allergy and Clinical Immunology, ISSN 0091-6749, E-ISSN 1097-6825, Vol. 127, no 5, p. 1286-1293.e6Article in journal (Refereed)
    Abstract [en]

    Background: In 2009, we reported a novel form of delayed anaphylaxis to red meat that is related to serum IgE antibodies to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Most of these patients had tolerated meat for many years previously. The implication is that some exposure in adult life had stimulated the production of these IgE antibodies. Objectives: We sought to investigate possible causes of this IgE antibody response, focusing on evidence related to tick bites, which are common in the region where these reactions occur.

    Methods: Serum assays were carried out with biotinylated proteins and extracts bound to a streptavidin ImmunoCAP.

    Results: Prospective studies on IgE antibodies in 3 subjects after tick bites showed an increase in levels of IgE to alpha-gal of 20fold or greater. Other evidence included (1) a strong correlation between histories of tick bites and levels of IgE to alpha-gal (chi(2) = 26.8, P < .001), (2) evidence that these IgE antibodies are common in areas where the tick Amblyomma americanum is common, and (3) a significant correlation between IgE antibodies to alpha-gal and IgE antibodies to proteins derived from A americanum (r(s) = 0.75, P < .001).

    Conclusion: The results presented here provide evidence that tick bites are a cause, possibly the only cause, of IgE specific for alpha-gal in this area of the United States. Both the number of subjects becoming sensitized and the titer of IgE antibodies to alpha-gal are striking. Here we report the first example of a response to an ectoparasite giving rise to an important form of food allergy.

  • 36. Cornmins, Scott P.
    et al.
    Kelly, Libby A.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    James, Hayley R.
    Pochan, Shawna L.
    Peters, Edward J.
    Lundbäck, Bo
    Nganga, Lucy W.
    Cooper, Philip J.
    Hoskins, Janelle M.
    Eapen, Saju S.
    Matos, Luis A.
    McBride, Dane C.
    Heymann, Peter W.
    Woodfolk, Judith A.
    Perzanowski, Matthew S.
    Platts-Mills, Thomas A. E.
    Galactose-alpha-1,3-Galactose-Specific IgE Is Associated with Anaphylaxis but Not Asthma2012In: American Journal of Respiratory and Critical Care Medicine, ISSN 1073-449X, E-ISSN 1535-4970, Vol. 185, no 7, p. 723-730Article in journal (Refereed)
    Abstract [en]

    Rationale: IgE antibodies to the mammalian oligosaccharide galactose-alpha-1,3-galactose (alpha-gal) are common in the southeastern United States. These antibodies, which are induced by ectoparasitic ticks, can give rise to positive skin tests or serum assays with cat extract. Objectives: To evaluate the relationship between IgE antibodies to alpha-gal and asthma, and compare this with the relationship between asthma and IgE antibodies to Fel d 1 and other protein allergens. Methods: Patients being investigated for recurrent anaphylaxis, angioedema, or acute urticaria underwent spirometry, exhaled nitric oxide, questionnaires, and serum IgE antibody assays. The results were compared with control subjects and cohorts from the emergency department in Virginia (n = 130), northern Sweden (n = 963), and rural Kenya (n = 131). Measurements and Main Results: Patients in Virginia with high-titer IgE antibodies to a-gal had normal lung function, low levels of exhaled nitric oxide, and low prevalence of asthma symptoms. Among patients in the emergency department and children in Kenya, there was no association between IgE antibodies to a-gal and asthma (odds ratios, 1.04 and 0.75, respectively). In Sweden, IgE antibodies to cat were closely correlated with IgE antibodies to Fel d 1 (r = 0.83) and to asthma (P < 0.001). Conclusions: These results provide a model of an ectoparasite-induced specific IgE response that can increase total serum IgE without creating a risk for asthma, and further evidence that the main allergens that are causally related to asthma are those that are inhaled.

  • 37.
    Ekerljung, L
    et al.
    Department of Internal Medicine, Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Andersson, Å
    Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institute, Stockholm.
    Sundblad, B-M
    Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institute, Stockholm.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, K
    Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institute, Stockholm.
    Ahlstedt, S
    Center for Allergy Research, Karolinska Institute, Stockholm, Sweden.
    Dahlén, S-E
    Center for Allergy Research, Karolinska Institute, Stockholm, Sweden.
    Lundbäck, B
    Department of Internal Medicine, Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Has the increase in the prevalence of asthma and respiratory symptoms reached a plateau in Stockholm, Sweden?2010In: The International Journal of Tuberculosis and Lung Disease, ISSN 1027-3719, E-ISSN 1815-7920, Vol. 14, no 6, p. 764-771Article in journal (Refereed)
    Abstract [en]

    SETTING: An increase in the prevalence of asthma has previously been reported worldwide. However, the current trend is debatable.

    OBJECTIVE: To assess changes in the prevalence of asthma and respiratory symptoms in a defined study area in Stockholm, Sweden, using identical methods.

    DESIGN: A questionnaire was sent by mail in 1996 and 2007 to randomly selected subjects aged 20-69 years. On both occasions, 8000 subjects received the questionnaire, with response rates of 72% and 68%, respectively. Questions on asthma, respiratory symptoms, asthma medication and possible determinants were included. Logistic regression analysis was used to assess determinants.

    RESULTS: Ever asthma increased from 8.7% in 1996 to 11.0% in 2007 and physician-diagnosed asthma from 7.6% to 9.3%. The proportion of asthma patients reporting one to two symptoms increased by 14% during the study period. There were few significant changes in the prevalence of respiratory symptoms: wheeze in the previous 12 months (15.9-17.3%), wheezing with breathlessness apart from cold (3.2-4.1%) and recurrent wheeze (8.3-6.8%). There was no major difference in the risk factor pattern between the surveys.

    CONCLUSION: An increase in the prevalence of asthma with few symptoms as well as an unchanged prevalence of symptoms was demonstrated, which may indicate a change in diagnostic practices.

  • 38.
    Ekerljung, Linda
    et al.
    Krefting Research Centre, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Bossios, Apostolos
    Krefting Research Centre, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Lötvall, Jan
    Krefting Research Centre, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Olin, Anna-Carin
    Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Rönmark, Eva
    Obstructive Lung Disease in Northern Sweden (OLIN), Dept of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden.
    Wennergren, Göran
    Department of Paediatrics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Torén, Kjell
    Department of Environmental & Occupational Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Lundbäck, Bo
    Obstructive Lung Disease In Northern Sweden (OLIN) studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden.
    Multi-symptom asthma as an indication of disease severity in epidemiology2011In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 38, no 4, p. 825-832Article in journal (Refereed)
    Abstract [en]

    Epidemiological questionnaires have failed to identify individuals with severe asthma. The extent of symptoms of asthma can, however, be easily established in epidemiology, by identification of multiple symptoms. We hypothesise that reporting of multiple symptoms of asthma reflects uncontrolled disease and is a sign of more severe asthma. The aims of the current study were, therefore, to determine the prevalence and determinants of multi-symptom asthma.

    A postal questionnaire was sent to 30,000 randomly selected individuals aged 16–75 yrs. A subgroup underwent clinical examinations. Multi-symptom asthma was defined as reported physician-diagnosed asthma, use of asthma medication, recurrent wheeze, attacks of shortness of breath and at least one additional respiratory symptom.

    The prevalence of multi-symptom asthma was 2.0%, and it was more common among females (2.4 versus 1.5%; p<0.001) and those with a body mass index >30 kg·m-2. Multi-symptom asthmatics had lower forced expiratory volume in 1 s, higher exhaled nitric oxide fraction and more pronounced hyperresponsiveness. Family history of both asthma and allergy (OR 7.3), and occupational exposure to gas dust or fumes (OR 2.0) were also significant risk factors.

    Multi-symptom asthmatics comprise 2% of the general population; multi-symptom asthma is related to signs of more severe disease and could be used as an epidemiological marker of disease severity.

  • 39. Ekerljung, Linda
    et al.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Obstructive Lung Disease In Northern Sweden (OLIN) Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden.
    Larsson, Kjell
    Sundblad, Britt-Marie
    Bjerg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Obstructive Lung Disease In Northern Sweden (OLIN) Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden.
    Ahlstedt, Staffan
    Dahlén, Sven-Erik
    Lundbäck, Bo
    No further increase of incidence of asthma: incidence, remission and relapse of adult asthma in Sweden2008In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 102, no 12, p. 1730-1736Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Knowledge about time trends of disease patterns in society is essential for planning and prioritizing health care resources. Longitudinal population-based studies on asthma are scarce but provide an opportunity to assess incidence, remission and relapse of asthma, and their determinants, which were the objectives of the present study.

    METHODS: A postal questionnaire was sent on two occasions, 1996 and 2006, to a randomly selected sample of subjects aged 20-69 years in 1996. The response rates were 72% and 83%, respectively, and in total 4479 subjects participated in both surveys. The questionnaire included questions on asthma, respiratory symptoms and possible determinants. Logistic regression was used to assess determinants.

    RESULTS: Cumulative incidence of asthma was 2.4% (men 1.9%; women 2.8%, p=0.06). Family histories of asthma (OR 2.31, CI 95% 1.42-3.76), rhinitis (OR 2.25, CI 95% 1.43-3.53) and being an ex-smoker (OR 2.17, CI 95% 1.27-3.71) were determinants for incident asthma. The 10-year remission of asthma was 14.6% and inversely associated with rhinitis. Relapse was found in 38% of eligible subjects.

    CONCLUSIONS: The current study with high participation rates concludes that the incidence of asthma among adults has been stable in Sweden for the past two decades. Remission was associated with mild disease at study start. Relapse in adults has rarely been reported previously and provide new insight in the course of asthma. Low remission and high relapse further support the view of asthma as a chronic disease; possibly representing fluctuations of the disease over time.

  • 40. Ekerljung, Linda
    et al.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Department of Internal Medicine, Krefting Research Centre, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Obstructive Lung Disease In Northern Sweden (OLIN) studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden.
    Lötvall, Jan
    Wennergren, Göran
    Torén, Kjell
    Lundbäck, Bo
    Questionnaire layout and wording influence prevalence and risk estimates of respiratory symptoms in a population cohort2013In: Clinical Respiratory Journal, ISSN 1752-6981, E-ISSN 1752-699X, Vol. 7, no 1, p. 53-63Article in journal (Refereed)
    Abstract [en]

    Objective: Results of epidemiological studies are greatly influenced by the chosen methodology. The study aims to investigate how two frequently used questionnaires (Qs), with partly different layout, influence the prevalence of respiratory symptoms.

    Study Design and Setting: A booklet containing two Qs, the Global Allergy and Asthma European Network Q and the Obstructive Lung Disease in Northern Sweden Q, was mailed to 30 000 subjects aged 16-75 years in West Sweden; 62% responded. Sixteen questions were included in the analysis: seven identical between the Qs, four different in set-up and five with the same layout but different wording. Comparisons were made using differences in proportions, observed agreement and Kappa statistics.

    Results: Identical questions yielded similar prevalences with high observed agreement and kappa values. Questions with different set-up or differences in wording resulted in significantly different prevalences with lower observed agreement and kappa values. In general, the use of follow-up questions, excluding subjects answering no to the initial question, resulted in 2.9-6.7% units lower prevalence.

    Conclusion: The question set-up has great influences on epidemiological results, and specifically questions that are set up to be excluded based on a previous no answer leads to lower prevalence compared with detached questions. Therefore, Q layout and exact wording of questions has to be carefully considered when comparing studies.

  • 41.
    Ekerljung, Linda
    et al.
    Department of Internal Medicine, VBG-Group Centre for Asthma and Allergy Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Sundblad, Britt-Marie
    Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Kjell
    Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden.
    Lundbäck, Bo
    Department of Internal Medicine, VBG-Group Centre for Asthma and Allergy Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Incidence and prevalence of adult asthma is associated with low socio-economic status2010In: The clinical respiratory journal, ISSN 1752-699X, Vol. 4, no 3, p. 147-156Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Low socio-economic status is often related to health problems; however, previous studies on asthma, usually cross-sectional, yield inconsistent results. In this study, longitudinal and cross-sectional data on the association between socio-economic status and asthma as well as respiratory symptoms among adults are presented.

    METHODS: A postal questionnaire was sent on two occasions, 1996 and 2006, to a randomly selected sample of subjects aged 20-69 years in 1996. In total, 4479 subjects participated in both surveys. The questionnaire included questions on asthma, respiratory symptoms and possible determinants. Logistic regression analysis, adjusted for potential confounders, was used to study the association between asthma, respiratory symptoms and socio-economic status.

    RESULTS: Manual workers in service had the highest prevalence and cumulative incidence for all investigated symptoms and asthma. Despite a large decrease in smokers, the increase in incident bronchitic symptoms was higher than the increase of incident asthma and incident asthmatic symptoms. Low socio-economic status, rhinitis and a family history of asthma were risk factors for having and developing asthma and respiratory symptoms.

    CONCLUSION: Low socio-economic status is significantly associated with an increased risk for prevalent and incident asthma and respiratory symptoms in this longitudinal population-based survey. The increase in risk was most pronounced in manual workers. Several studies have recently shown an association between low socio-economic status and respiratory symptoms and we conclude that asthma can not be considered as a disease that mainly affects the middle and upper socio-economic classes.

  • 42. Eriksson, Berne
    et al.
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bossios, Apostolos
    Bjerg, Anders
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Only severe COPD is associated with being underweight: results from a population survey.2016In: ERJ open research, E-ISSN 2312-0541, Vol. 2, no 3Article in journal (Refereed)
    Abstract [en]

    Low body mass index (BMI) and malnutrition in chronic obstructive pulmonary disease (COPD) are associated with a poor prognosis. The prevalence of underweight, as well as overweight, in severity grades of COPD is sparsely investigated in studies of the general population and the associated patterns of risk factors are not well established. The aim of the present study was to determine the association between severity grades of airflow limitation in COPD, and both underweight and obesity when corrected for possible confounding factors. The study is based on pooled data from the OLIN (Obstructive Lung Disease in Northern Sweden) studies. Complete records with lung function, BMI and structured interview data were available from 3942 subjects (50.7% women and 49.3% men). COPD and severity grading were defined using the Global Initiative for Chronic Obstructive Lung Disease criteria. In sensitivity analyses, the lower limit of normal was used. The prevalence of underweight was 7.3% in severe COPD (grades 3 and 4) versus 2.0% in those with normal spirometry. The prevalence of obesity increased from 9.7% in grade 1, to 16.3% in grade 2 and 20.0% in severe COPD, versus 17.7% in those with normal spirometry. In adjusted analysis, of the COPD severity grades, only severe COPD was associated with underweight (OR 3.24, 95% CI 1.0004-10.5), while the COPD severity grades tended to be inversely associated with overweight.

  • 43.
    Eriksson, Berne
    et al.
    Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden; Department of Internal Medicine, Central County Hospital of Halmstad, Halmstad, Sweden.
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Ekerljung, Linda
    Krefting Research Centre, Institute of Medicine, University of Gothenburg , Gothenburg, Sweden.
    Axelsson, Malin
    Department of Care Science, Faculty of Health and Society, Malmö University, Malmö, Sweden.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundbäck, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
    Pattern of Cardiovascular Comorbidity in COPD in a Country with Low-smoking Prevalence: Results from Two-population-based Cohorts from Sweden2018In: COPD: Journal of Chronic Obstructive Pulmonary Disease, ISSN 1541-2555, E-ISSN 1541-2563, Vol. 15, no 5, p. 454-463Article in journal (Refereed)
    Abstract [en]

    Cardiovascular diseases are the most common comorbidities in COPD, due to common risk factors such as smoking. The prevalence of current smokers in Sweden has decreased over four decades to around 10%. The aim of the present study was to investigate the prevalence, distribution and associations of cardiovascular comorbidities in COPD by disease severity in two large areas of Sweden, both with low-smoking prevalence. Data from clinical examinations in 2009-2012, including spirometry and structured interview, from two large-scale population studies, the West Sweden Asthma Study (WSAS) and the OLIN Studies in Northern Sweden, were pooled. COPD was defined using post-bronchodilator spirometry according to the fixed ratio FEV1/FVC <0.70 and the lower limit of normal (LLN5th percentile) of the ratio of FEV1/FVC. Of the 1839 subjects included, 8.7% and 5.7% had COPD according to the fixed ratio and the LLN criterion. Medication for heart disease or hypertension among those with moderate-to-severe COPD was more common than among those without COPD (fixed ratio definition of COPD: 51% vs. 23%, p < 0.001; LLN definition: 42% vs. 24%, p = 0.002). After adjusting for known risk factors for COPD, including smoking, age, socio-economic status, and occupational exposure for gas, dust and fumes, only heart failure remained significantly, and independently, associated with COPD, irrespective of the definitions of COPD. Though a major decrease in smoking prevalence, the pattern of cardiovascular comorbidities in COPD still remains similar with previously performed studies in Sweden and in other Westernized countries as well.

  • 44. Eriksson, Berne
    et al.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Muellerova, Hana
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundback, Bo
    Association of heart diseases with COPD and restrictive lung function - Results from a population survey2013In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 107, no 1, p. 98-106Article in journal (Refereed)
    Abstract [en]

    Introduction: Few studies have explored the association of COPD, based on GOLD definition, with heart diseases. The relationship between restrictive lung function impairment and heart diseases is still poorly studied on a population level. Objectives: To explore the association of COPD and restrictive lung function impairment, respectively, with heart diseases in the general population. Design: This is a cross-sectional study of 642 randomly selected 22- to 72-year-old subjects in northern Sweden. COPD was defined according to GOLD. Restrictive lung function was defined as pre-bronchodilator FVC <80% of predicted value and FEV1/FVC >= 0.7. Results: The prevalence of ischemic heart disease was 4% in subjects with normal spirometry, 13% in subjects with COPD, and 21% in those with restrictive lung function. The prevalence of heart diseases increased with COPD severity. On the other hand, the prevalence of COPD was particularly high in the group reporting myocardial infarction. In subjects reporting different heart diseases, the prevalence of restrictive lung function was high. In multivariate analyses including age, sex, smoking habits, family history of obstructive airway disease, body mass index, and socio-economic status as independent variables, COPD was associated with ischemic heart disease (odds ratio [OR] 2.61; 95% confidence interval [CI] 1.12-6.08) and ischemic heart disease with COPD (OR 2.40; 95% CI 1.03-5.61). Conclusion: The study shows a strong association between COPD and cardiovascular diseases and indicates a strong association between restrictive lung function and heart diseases. Both obstructive and restrictive lung function impairments were common among subjects with heart diseases and vice versa.

  • 45.
    Eriksson, J
    et al.
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Ekerljung, L
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Lötvall, J
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Pullerits, T
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Wennergren, G
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Torén, K
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Lundbäck, B
    Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Growing up on a farm leads to lifelong protection against allergic rhinitis2010In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 65, no 11, p. 1397-1403Article in journal (Refereed)
    Abstract [en]

    Background: Various studies have reported a low prevalence of allergic rhinitis in farmers and farmers' children. We sought to investigate whether the protective effect of childhood farm environment is conserved throughout adulthood and how it corresponds to different degrees of urbanization.

    Methods: A questionnaire on respiratory health was mailed in 2008 to 30 000 randomly selected subjects aged 16-75 in West Sweden, 29 218 could be traced and 18 087 (62%) responded. The questionnaire included questions on allergic rhinitis, asthma, respiratory symptoms and possible determinants.

    Results: When stratified into age groups of 15 years, subjects that lived on a farm during their first 5 years of life had a lower prevalence of allergic rhinitis in all groups, even among the oldest (61-75 years). The negative correlation between childhood farm living and prevalence of allergic rhinitis was similar in 46-75 years of age (OR 0.82; 95% CI 0.70-0.95) as in 16-45 years of age (OR 0.78; 0.64-0.95). There was a significant trend of increasing prevalence of allergic rhinitis with increasing degree of urbanization independent of the effect of childhood farm living.

    Conclusions: We found a lifelong protective effect of childhood farm living on the prevalence of allergic rhinitis. In addition, we found an increasing prevalence of allergic rhinitis with increasing degree of urbanization both in those raised on a farm and those not, thus emphasizing the influence of both childhood and adult exposure for the development of allergic disease.

  • 46. Eriksson, J.
    et al.
    Ekerljung, L.
    Sundblad, B. -M
    Lotvall, J.
    Toren, K.
    Rönnmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, K.
    Lundback, B.
    Cigarette smoking is associated with high prevalence of chronic rhinitis and low prevalence of allergic rhinitis in men2013In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 68, no 3, p. 347-354Article in journal (Refereed)
    Abstract [en]

    Background The harmful effects of tobacco smoke on human health, including respiratory health, are extensive and well documented. Previous data on the effect of smoking on rhinitis and allergic sensitization are inconsistent. We sought to investigate how smoking correlates with prevalence of allergic and chronic rhinitis among adults in Sweden. Methods The study population comprised 27879 subjects derived from three large randomly selected cross-sectional population surveys conducted in Sweden between 2006 and 2008. The same postal questionnaire on respiratory health was used in the three surveys, containing questions about obstructive respiratory diseases, rhinitis, respiratory symptoms and possible determinants of disease, including smoking habits. A random sample from one of the cohorts underwent a clinical examination including skin prick testing. Results Smoking was associated with a high prevalence of chronic rhinitis in both men and women and a low prevalence of allergic rhinitis in men. These associations were dose dependent and remained when adjusted for a number of possible confounders in multiple logistic regression analysis. Prevalence of chronic rhinitis was lowest in nonsmokers and highest in very heavy smokers (18.5% vs 34.5%, P<0.001). Prevalence of sensitization to common airborne allergens was lower in current smokers (25.9%, P=0.008) and ex-smokers (28.2%, P=0.022) than in nonsmokers (38.5%). Conclusion We found that smoking was associated with a high prevalence of chronic rhinitis in both sexes and a low prevalence of allergic rhinitis in men. The associations were dose dependent and remained when adjusting for several possible confounders.

  • 47. Eriksson, Jonas
    et al.
    Bjerg, Anders
    Lotvall, Jan
    Wennergren, Goran
    Rönnmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Toren, Kjell
    Lundback, Bo
    Rhinitis phenotypes correlate with different symptom presentation and risk factor patterns of asthma2011In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 105, no 11, p. 1611-1621Article in journal (Refereed)
    Abstract [en]

    Background: Asthma and rhinitis frequently coexist, but no population study has previously determined the relationship between nasal comorbidities and symptom expression and risk factors of asthma.

    Methods: In 2008, a postal questionnaire on respiratory health was sent to 30 000 randomly selected subjects aged 16-75 years in West Sweden; 29218 could be traced and 18 087 (62%) responded. The questionnaire included questions on asthma, rhinitis, chronic rhinosinusitis, respiratory symptoms and possible determinants.

    Results: Prevalence of allergic rhinitis in asthma was 63.9% and of asthma in allergic rhinitis 19.8%. Prevalence of chronic rhinosinusitis in asthma was 8.4% and of asthma in chronic rhinosinusitis 24.4%. Asthma subjects with chronic rhinitis, or chronic rhinosinusitis, had more symptoms of asthma and bronchitis than those without rhinitis (p < 0.001). There was an obvious trend of higher ORs for various environmental exposures including occupational exposure to dust, gases and fumes (OR 2.32 vs. OR 1.44), visible mould at home (OR 1.72 vs. OR 1.27) and water damage at home (OR 1.82 vs. OR 1.06) for asthma with chronic rhinosinusitis than for asthma with allergic rhinitis. Family history of allergy yielded a higher OR for asthma with allergic rhinitis than with asthma with chronic rhinosinusitis (OR 7.15 vs. OR 4.48).

    Conclusion: Considerable overlap between asthma and nasal comorbidities was documented, confirming a close relationship between nasal disease and asthma. Allergic rhinitis, chronic rhinitis and chronic rhinosinusitis were associated with different risk factor patterns and symptom expression of asthma. Thus, different nasal comorbidities may reflect different phenotypes of asthma. (C) 2011 Elsevier Ltd. All rights reserved.

  • 48. Eriksson, Jonas
    et al.
    Ekerljung, Linda
    Bossios, Apostolos
    Bjerg, Anders
    Wennergren, Göran
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Torén, Kjell
    Lötvall, Jan
    Lundbäck, Bo
    Aspirin-intolerant asthma in the population: prevalence and important determinants2015In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 45, no 1, p. 211-219Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Population-based studies on aspirin-intolerant asthma are very few and no previous population study has investigated risk factors for the condition.

    OBJECTIVE: To investigate the prevalence and risk factors of aspirin-intolerant asthma in the general population.

    METHODS: A questionnaire on respiratory health was mailed to 30 000 randomly selected subjects aged 16-75 years in West Sweden, 29 218 could be traced and 18 087 (62%) responded. The questionnaire included questions on asthma, respiratory symptoms, aspirin-induced dyspnea and possible determinants.

    RESULTS: The prevalence of aspirin-intolerant asthma was 0.5%, 0.3% in men and 0.6% in women (p=0.014). Sick leave, emergency visits due to asthma and all investigated lower respiratory symptoms were more common in aspirin-intolerant asthma than in aspirin-tolerant asthma. Obesity was a strong risk factor for aspirin-intolerant asthma (BMI>35: OR 12.1; 95% CI 2.49-58.5) and there was a dose-response relationship between increasing body mass index and risk of aspirin-intolerant asthma. Obesity, airborne occupational exposure and visible mold at home were considerably stronger risk factors for aspirin-intolerant asthma than for aspirin-tolerant asthma. Current smoking was a risk factor for aspirin-intolerant asthma (OR 2.55; 95% CI 1.47-4.42), but not aspirin-tolerant asthma.

    CONCLUSION: Aspirin-intolerant asthma identified in the general population was associated with a high burden of symptoms, uncontrolled disease and a high morbidity. Increasing body mass index increased the risk of aspirin-intolerant asthma in a dose-response manner. A number of risk factors, including obesity and current smoking, were considerably stronger for aspirin-intolerant asthma than for aspirin-tolerant asthma.

  • 49.
    Eriksson, Jonas
    et al.
    Department of Internal Medicine/Krefting Research Centre Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Ekerljung, Linda
    Department of Internal Medicine/Krefting Research Centre Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Pullerits, Teet
    Department of Internal Medicine/Krefting Research Centre Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Holmberg, Kenneth
    Department of Internal Medicine/Respiratory Medicine and Allergology, Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Internal Medicine/Krefting Research Centre ; The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Lötvall, Jan
    Department of Internal Medicine/Krefting Research Centre Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Lundbäck, Bo
    Department of Internal Medicine/Krefting Research Centre Sahlgrenska Academy, University of Gothenburg, Gothenburg.
    Prevalence of chronic nasal symptoms in West Sweden: risk factors and relation to self-reported allergic rhinitis and lower respiratory symptoms2011In: International Archives of Allergy and Immunology, ISSN 1018-2438, E-ISSN 1423-0097, Vol. 154, no 2, p. 155-163Article in journal (Refereed)
    Abstract [en]

    Background: There are few population-based studies on chronic nasal symptoms and little is known about their prevalence and determinants, or their association with allergic rhinitis and asthma.

    Methods: A questionnaire focused on respiratory symptoms and conditions was mailed in 2008 to 30,000 randomly selected subjects aged 16-75 years in West Sweden, 29,218 could be traced and 18,087 (62%) responded. The questionnaire included questions on self-reported allergic rhinitis, asthma, lower respiratory and nasal symptoms and possible determinants.

    Results: Nasal congestion was reported by 14.9% and runny nose by 13.1% of subjects. In total, 19.8% had chronic nasal symptoms. Subjects with chronic nasal symptoms had considerably more symptoms from the lower airways compared with nonrhinitic subjects and vice versa. Forty-seven percent of the subjects with chronic nasal symptoms had concurrent self-reported allergic rhinitis. Several hereditary and environmental factors were associated with chronic rhinitis, including family history of asthma [odds ratio (OR) 1.27; 95% confidence interval 1.07-1.50], family history of allergy (OR 1.74; 1.57-1.92) and current smoking (OR 1.39; 1.25-1.54). Further, chronic nasal symptoms were increasingly prevalent with an increasing degree of urbanization.

    Conclusion: The prevalence of chronic nasal symptoms in West Sweden was found to be high and strongly associated both with self-reported allergic rhinitis and symptoms from the lower airways. Moreover, several risk factors were identified for chronic nasal symptoms, including family history of allergy and asthma and smoking.

  • 50. Eriksson, Jonas
    et al.
    Ekerljung, Linda
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Dahlen, Barbro
    Ahlstedt, Staffan
    Dahlen, Sven-Erik
    Lundback, Bo
    Update of prevalence of self-reported allergic rhinitis and chronic nasal symptoms among adults in Sweden2012In: Clinical Respiratory Journal, ISSN 1752-6981, E-ISSN 1752-699X, Vol. 6, no 3, p. 159-168Article in journal (Refereed)
    Abstract [en]

    Background: Allergic rhinitis (AR) is the most common immunologic disease, and it renders a considerable burden on both sufferers and society. The prevalence of AR has been increasing worldwide over the past century. The aim of this study was to assess the present prevalence, risk factor patterns and comorbidity of self-reported AR and chronic nasal symptoms in different age groups in Stockholm, Sweden. Methods: A postal questionnaire was sent on two occasions, in 2006 to a population aged 30-80 years, randomly selected 10 years previously, and in 2007 to a randomly selected sample of subjects aged 20-69 years. The response rates were 83% and 68%, respectively, and in total, 9792 subjects participated. The questionnaire included questions on self-reported AR, asthma, respiratory and nasal symptoms and possible determinants. Results: The prevalence of self-reported AR was 28.0% (men 26.6%, women 29.1%, P < 0.01) similar to 10 years previously and 33.6% in ages 3040 years. Allergic heredity [odds ratio (OR) 4.76, confidence interval (CI) 95% 4.255.33], physician-diagnosed asthma (OR 5.29, CI 95% 4.496.24) and occupational exposure to dust, gases and fumes (OR 1.49, CI 95% 1.301.72) were determinants for AR. Prevalence of chronic nasal congestion was 16.1% and of chronic rhinorrhea 14.1%. Conclusions: As a basis for understanding the disease, as well as in planning and prioritising health-care resources, the study provides information about the current prevalence and determinants of self-reported AR and chronic nasal symptoms. Further, comparing with previous studies, the present study suggests that a plateau in the prevalence of AR may have been reached in Sweden. Please cite this paper as: Eriksson J, Ekerljung L, Ronmark E, Dahlen B, Ahlstedt S, Dahlen S-E and Lundback B. Update of prevalence of self-reported allergic rhinitis and chronic nasal symptoms among adults in Sweden. Clin Respir J 2012; 6: 159168.

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