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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.
    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, E435-E442 p.Article 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.

  • 2.
    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)
  • 3.
    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, 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.

  • 4.
    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.

  • 5.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eriksson, Berne
    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
    Jansson, Sven-Arne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindberg, Anne
    Lundbäck, Bo
    Decreased prevalence of moderate to severe COPD over 15 years in northern Sweden2016In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 114, 103-110 p.Article 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.

  • 6.
    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.

  • 7.
    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, 1- p.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.

  • 8.
    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, 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.

  • 9. 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, E905-E912 p.Article 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.

  • 10.
    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, 741-8 p.Article 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.

  • 11.
    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, 146-153 p.Article 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.

  • 12. Hagstad, Stig
    et al.
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Obstructive Lung Disease In Northern Sweden (OLIN) Studies, Norrbotten County Council, Luleå, Sweden.
    Bjerg, Anders
    Ekerljung, Linda
    Ye, Xiong
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Obstructive Lung Disease In Northern Sweden (OLIN) Studies, Norrbotten County Council, Luleå, Sweden.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. Unit of Research , Education and Development - Luleå, Umeå University .
    Torén, Kjell
    Lötvall, Jan
    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, Norrbotten County Council, Luleå, Sweden.
    Lundbäck, Bo
    Prevalence and risk factors of COPD among never-smokers in two areas of Sweden: Occupational exposure to gas, dust or fumes is an important risk factor2015In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 109, no 11, 1439-1445 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Although active tobacco smoking is the main risk factor for COPD, COPD is not uncommon also among never-smokers. Different study locations along with different spirometric definitions of COPD have historically yielded different prevalence estimates of the disease.

    AIM: To study current prevalence and risk factors of COPD among never-smokers in two areas of Sweden.

    METHODS: Data collected in 2008-2012 within the West Sweden Asthma Study and Obstructive Lung Disease in Northern Sweden Studies was pooled. The study population consisted of 1839 subjects who participated in spirometry and interviews. COPD was defined as post-bronchodilator a) FEV1/(F)VC < 0.7, b) FEV1/FVC < 0.7 and c) FEV1/FVC < lower limit of normal.

    RESULTS: Of the 1839 subjects, 967 (52.6%) were never-smokers. Among the never-smoking subjects, the prevalence of COPD according to definitions a-c was 7.7%, 4.9% and 3.0%, respectively. The corresponding prevalence of GOLD grade ≥2 was 2.0%, 1.4% and 1.3%. No significant difference in prevalence between the two study areas was observed. In never-smokers, occupational exposure to gas, dust or fumes (GDF) was significantly associated with both COPD (OR 1.85, 95% CI 1.03-3.33), and GOLD ≥2 (OR 4.51, 1.72-11.9) according to definition a), after adjusting for age, educational level and exposure to passive smoking at work.

    CONCLUSION: Depending on definition, prevalence of COPD among never-smokers was 3.0-7.7%, whereas GOLD ≥2 was present in 1.3-2.0%. Occupational exposure to GDF remained independently and significantly associated with COPD regardless of spirometric definition of the disease.

  • 13.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Epidemiological studies of asthma and allergic diseases in teenagers: methodological aspects and tobacco use2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Parental reports are often used in studies of asthma and allergic diseases in children. A change in respondent from parent to index subject usually occurs during adolescence. Little is known about the effects this change in method might have on the outcomes of a longitudinal study. Smoking is a major cause of respiratory symptoms among adults and environmental tobacco smoke (ETS) is a risk factor for asthma among children. Less is known about these associations among teenagers. In order to improve prevention of smoking, it is important to identify populations at risk of becoming smokers.      

    The aim of this thesis were to 1) evaluate the methodological change from parental to self-completion of a questionnaire about asthma and allergic diseases, and 2) to study determinants for, and respiratory health effects of ETS and personal smoking in teenagers.

    In 1996, a longitudinal study of asthma and allergic diseases among schoolchildren started within the Obstructive Lung Disease in Northern Sweden (OLIN) studies. All children in first and second grades (aged 7-8 years) in three municipalities, Luleå, Kiruna and Piteå (n=3,525) were invited and 97% participated by parental completion of a questionnaire. The cohort has been followed with annual questionnaires until age 16-17 years and with high participation rates (>91%). From age 12-13 years, the teenagers were the respondents and questions about their tobacco use were included. In addition to the questionnaire completed by the teenagers at age 13-14 years, a questionnaire was also distributed to a random sample of 10% of the parents and 294 participated (84%).  

    The parents and the teenagers reported a similar prevalence of asthma, respiratory symptoms, rhinitis, eczema and environmental factors. Two statistically significant differences were found: the teenagers reported a higher prevalence of wheezing during or after exercise (14% vs 8%, p<0.05), and having a dog in the home in the last 12 months (42% vs 29%, p<0.001). Answer agreement between parents and teenagers on questions about asthma was almost perfect with kappa values of 0.8-0.9. Corresponding kappa values for questions about respiratory symptoms and rhinitis were 0.3-0.6 and for eczema 0.5-0.6. Agreement about environmental factors varied from 0.2-0.9. Kappa values for parental smoking were 0.8-0.9. The risk factor pattern for allergic diseases was similar regardless of respondent, ie parent or teenager.

    The prevalence of smoking increased from 3% at 12-13 years to 6% at 14-15 years. Smoking was more common among girls, while the use of snus was more common among boys. Significant risk factors related to smoking among teenagers were smoking family members, female sex and living in an apartment. Having physician-diagnosed asthma did not prevent the teenagers from becoming smokers. Factors related to using snus were a smoking mother and male sex. 

    Daily smokers aged 16-17 years (9%) reported a significantly higher prevalence of wheezing and physician-diagnosed asthma compared to non-smokers. There was a significant dose-response association with higher prevalence of wheeze among those who smoked ≥11 cigarettes per day compared to those who smoked ≤10 per day. In multivariate analyses, maternal environmental tobacco smoke exposure was a significant risk factor for ever wheeze and physician-diagnosed asthma at age 16-17 years, while daily smoking was a risk factor for current wheeze.

    In conclusion, the methodological change of questionnaire respondent from parent to index subject did not substantially alter the findings of this longitudinal study. There were significant sex differences in the tobacco use: smoking was more common among girls and snus was more common among boys. The most important factor related to tobacco use was presence of family members who smoke. Both maternal ETS exposure and personal smoking was associated with asthma and wheeze in adolescence. ETS was associated with lifetime symptoms but daily smoking was more strongly associated with current symptoms.

  • 14.
    Hedman, Linnea
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Sunderby Cent Hosp Norrbotten, Dept Med, Obstruct Lung Dis No Sweden Studies, S-97189 Lulea, Sweden.
    Bjerg, Anders
    Perzanowski, Matthew
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Sunderby Cent Hosp Norrbotten, Dept Med, Obstruct Lung Dis No Sweden Studies, S-97189 Lulea, Sweden.
    Good agreement between parental and self-completed questionnaires about allergic diseases and environmental factors in teenagers2010In: Journal of Clinical Epidemiology, ISSN 0895-4356, E-ISSN 1878-5921, Vol. 63, no 7, 783-789 p.Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To study whether the methodological change from parent to index subject as questionnaire respondent affected the prevalence estimates and risk factor patterns for allergic diseases in a longitudinal study.

    STUDY DESIGN AND SETTING: A prospective study of asthma and allergic diseases among children was begun in 1996 within the Obstructive Lung Disease in Northern Sweden Study. In 2002, about 3,342 (95% of invited) teenagers (13 to 14 years) completed the annual questionnaire. A random sample of 294 (84% of invited) parents also completed the same extended International Study of Asthma and Allergies in Childhood questionnaire. Skin prick tests were performed in 1996 and 2000.

    RESULTS: There were no significant differences in the prevalence of rhinitis, eczema, or related environmental factors between parental and self-reports, except for the question of having a dog at home. The absolute agreement was high, whereas the kappa values were fair or moderate. Kappa values of questions regarding parental smoking were 0.8-0.9. Allergic sensitization was the major risk factor for both rhinitis and eczema, and the odds ratios were similar regardless of who reported the condition.

    CONCLUSION: The agreement between the parental and teenagers' reports was good, and the methodological change did not affect the study results.

  • 15.
    Hedman, Linnea
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    Sundberg, Sigrid
    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.
    Both environmental tobacco smoke and personal smoking are associated to asthma and wheeze among adolescentsManuscript (preprint) (Other academic)
  • 16.
    Hedman, Linnea
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindgren, Berit
    Perzanowski, Matthew
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Agreement between parental and self-completed questionnaires about asthma in teenagers2005In: Pediatric Allergy and Immunology, ISSN 0905-6157, E-ISSN 1399-3038, Vol. 16, 176-181 p.Article in journal (Refereed)
  • 17.
    Hedman, Linnéa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Andersson, Martin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    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.
    Environmental risk factors related to the incidence of wheeze and asthma in adolescence2015In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 45, no 1, 184-191 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Asthma is common among adolescents, but there are few population-based studies on the risk factors for incident asthma and wheeze at this age group OBJECTIVE: To study risk factors for incident asthma and wheeze in adolescence.

    METHOD: Within the Obstructive Lung Disease In Northern Sweden (OLIN) studies, a cohort of 3430 school children (age 7-8y) was recruited in 1996. In the present study, this cohort was followed from age 12 to 19y. At baseline (age 12y), 3151 participated and skin prick tests (SPT) were performed. The cohort was resurveyed annually and risk factors for the cumulative incidence of asthma and wheeze from age 12 to19y were analysed using multivariate Cox regression.

    RESULTS: Female sex (wheeze: HR1.4 95%CI 1.2-1.6; asthma: HR1.8 95%CI1.2-2.5) and a positive SPT to cat, dog or horse at baseline (wheeze: HR 1.6 95%CI 1.2-2.1; asthma: HR2.3 95%CI 1.4-4.0) were significantly associated with the cumulative incidence of wheeze and asthma. Increasing numbers of siblings were inversely related to the incidence of wheeze (HR0.9 95%CI 0.8-0.97) and asthma (HR0.8 95%CI 0.7-0.97). Parental asthma was related to the incidence of asthma (HR 1.8 95%CI 1.2-2.6) while ever smoking (HR 2.0 95%CI 1.6-2.4) and house dampness (HR 1.3 95%CI 1.1-1.6) were risk factors for the incidence of wheeze. Maternal ETS exposure increased the risk of incident asthma in non-sensitized subjects (HR 1.9 95%CI 1.0-3.7).

    CONCLUSION AND CLINICAL RELEVANCE: Several environmental risk factors related to the incidence of asthma and wheeze in adolescence were identified and may be possible targets for intervention and prevention.

  • 18.
    Hedman, Linnéa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Andersson, Martin
    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.
    Lundbäck, B
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Incidence of wheeze and asthma in adolescence in relation to environmental factorsManuscript (preprint) (Other academic)
  • 19.
    Hedman, Linnéa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Andersson, Martin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Stridsman, Caroline
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Evaluation of a tobacco prevention programme among teenagers in Sweden2015In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 5, no 5, e007673Article in journal (Refereed)
    Abstract [en]

    Objective: To study the prevalence of tobacco use among teenagers, to evaluate a tobacco prevention programme and to study factors related to participation in the prevention programme. Design and setting: Population-based prospective cohort study. Method: Within the Obstructive Lung disease in Northern Sweden (OLIN) studies, a cohort study about asthma in schoolchildren started in 2006. All children aged 7-8 years in three municipalities were invited to a questionnaire survey and 2585 (96%) participated. The cohort was followed up at age 11-12 years (n=2612, 95% of invited) and 14-15 years (n=2345, 88% of invited). In 2010, some of the children in the OLIN cohort (n=447) were invited to a local tobacco prevention programme and 224 (50%) chose to participate. Results: At the age of 14-15 years, the prevalence of daily smoking was 3.5%. Factors related to smoking were female sex, having a smoking mother, participation in sports and lower parental socioeconomic status (SES). The prevalence of using snus was 3.3% and risk factors were male sex, having a smoking mother, having a snus-using father and non-participation in the prevention programme. In the prevention programme, the prevalence of tobacco use was significantly lower among the participants compared with the controls in the cohort. Factors related to non-participation were male sex, having a smoking mother, lower parental SES and participation in sports. Conclusions: The prevalence of tobacco use was lower among the participants in the tobacco prevention programme compared with the non-participants as well as with the controls in the cohort. However, the observed benefit of the intervention may be overestimated as participation was biased by selection.

  • 20.
    Hedman, Linnéa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    The OLIN-studies, Norrbotten County Council, S-971 89 Luleå, Sweden .
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Conventional epidemiology underestimates the incidence of asthma and wheeze: a longitudinal population-based study among teenagers2012In: Clinical and translational allergy, ISSN 2045-7022, Vol. 2, no 1, 1- p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Because of shifts in the gender ratio and incidence and remission rates of asthma during the teen ages, the methodology of incidence studies among teenagers is important, i.e. if the time intervals between surveys are too long, the incident cases might not be properly identified. The aim was to study the impact of study design on the incidence rates of asthma and wheeze during the teen ages.

    METHODS: In a study about asthma and allergic diseases within the OLIN studies (Obstructive Lung Disease in northern Sweden), a cohort of school children (n = 3,430) was followed annually by questionnaire from age 8 yrs. In the endpoint survey (age 18 yrs) 2,582 (75% of original responders) participated. Incident cases from age 12-18 yrs were identified by two methods: annual questionnaire reports (AR) and baseline-endpoint surveys only (BE).

    RESULTS: The cumulative incidence of asthma and wheeze was significantly higher based on AR compared to BE. Compared to the incidence rates based on all the annual surveys, the calculated average annual rates based on BE were in general lower both among the boys and among the girls. There were no differences between boys and girls in incidence rates of asthma or wheeze during the early teen years. However, from the age of 15 years, the annual incidence rates were significantly or borderline significantly higher among girls than boys. At onset, the additional cases of current asthma identified by AR had significantly less severe asthma than those identified in BE (p < 0.02).

    CONCLUSION: the size of the incidence of asthma and wheeze during the teen ages was influenced by study design. By using the conventional prospective study design with longer follow-up time, the incidence was underestimated.

  • 21.
    Hedman, Linnéa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    Sundberg, Sigrid
    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.
    Both environmental tobacco smoke and personal smoking is related to asthma and wheeze in teenagers2011In: Thorax, ISSN 0040-6376, E-ISSN 1468-3296, Vol. 66, no 1, 20-25 p.Article in journal (Refereed)
    Abstract [en]

    Background: Environmental tobacco smoke (ETS) has been reported as a significant risk factor for childhood asthma. Among adults, personal smoking is a major cause of respiratory symptoms and diseases. The effects of these exposures on the prevalence of asthma and wheeze among teenagers are less well known.

    Objective: The aim was to study the independent and combined effects of ETS and personal smoking on the prevalence of asthma and wheeze in teenagers.

    Methods: A longitudinal study of asthma and allergic diseases in schoolchildren has been in progress in Northern Sweden since 1996. All children aged 7–8 years in three municipalities were invited and 3430 (97%) participants have been followed by annual questionnaires. At the age 16–17 years, 82% of the initial participants took part in the 2005 survey.

    Results: Prevalence of physician-diagnosed asthma, ever wheeze and current wheeze was significantly higher among those exposed to maternal ETS and among daily smokers. In multivariate analyses, maternal ETS was a significant risk factor for physician-diagnosed asthma and ever wheeze (OR 1.3–1.5) and personal daily smoking for current wheeze (OR 2.0). ORs for asthma and ever wheeze were highest among daily smokers who were also exposed to maternal ETS with ORs of 1.7 and 2.5, respectively. A significant dose–response association between number of cigarettes/day and the prevalence of wheeze was also found.

    Conclusions: Both ETS and personal smoking were significantly related to asthma and wheeze in teenagers. Maternal ETS exposure was associated with lifetime symptoms, but daily smoking among the teenagers was more strongly related to current symptoms.

  • 22.
    Hedman, Linnéa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg Bäcklund, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Perzanowski, Matthew
    Sundberg, Sigrid
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Factors related to tobacco use among teenagers2007In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 101, no 3, 496-502 p.Article in journal (Refereed)
    Abstract [en]

    AIM: To examine tobacco use among teenagers, identify factors related to tobacco use, as well as evaluate the outcome of a smoking prevention program.

    METHODS: From age 7/8 to 14/15, annual questionnaires about asthma and allergy have been completed in the OLIN paediatric study in Northern Sweden. From 12/13 years, questions about tobacco use, i.e. smoking and snuff, were added. A smoking prevention program was performed during 2 years.

    RESULTS: Any tobacco use increased from 5.0% at age 12/13 years, to 14.4% at age 14/15. At age 14/15 years, the prevalence of tobacco use was significantly higher among boys than girls (16.7 and 12.0%, respectively). More girls than boys smoked (8.9 and 2.8%, respectively), while use of snuff was more common among the boys (15.6 and 4.2%, respectively). Significant risk factors for smoking were any of the family members currently smoking, OR 6.1 (95% CI 4.0-9.3) and a physician-diagnosed asthma at the age of 14/15 years, OR 1.9 (95% CI 1.2-3.0). A protective factor against tobacco use was participation in sports, OR 0.3 (95% CI 0.2-0.4). The prevention program did not result in less tobacco use, although it may have delayed smoking initiation.

    CONCLUSION: The patterns of tobacco use differed significantly between boys and girls. Though any tobacco use was more common among boys, girls were more likely to smoke, and boys were more likely to use snuff. Having asthma did not prevent the teenagers from smoking. Since having a smoking family member was the major risk factor for tobacco use, prevention programs should be directed at smoking families in addition to the individuals.

  • 23. James, Hayley R
    et al.
    Perzanowski, Matthew S.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Hedman, Linnéa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Bjerg, Anders
    Schuyler, Alexander J
    Workman, Lisa J
    Lundback, Bo
    Platts-Mills, Thomas A E
    IgE Antibodies to Mammalian Allergens Are a Major Risk Factor for Prevalence, Severity, and Persistence of Asthma in Northern Sweden2015In: Journal of Allergy and Clinical Immunology, ISSN 0091-6749, E-ISSN 1097-6825, Vol. 135, no 2, AB22-AB22 p.Article in journal (Other academic)
    Abstract [en]

    IgE to mammalian allergens can contribute significantly to asthma risk. Studying the details of the relationship between animal sensitization and asthma is simpler in an environment where mite, fungal, and cockroach allergens make little or no contribution to asthma risk. Methods: Quantitative assays for IgE to eight allergens were carried out on 963 sera from 19-year-olds in a population-based cohort in northern Sweden, and associations with questionnaire data from ages 7, 12, and 19 on asthma symptoms, diagnosis, and treatment were tested. Results: Overall, 79 (53%) of the students with a physician diagnosis of asthma were positive to one or more of the mammalian allergens (cat, dog, or horse danders) tested. Of the allergens assessed, only mammalian allergens, birch, and timothy grass pollen showed a significant relationship with asthma diagnosis. Multivariate analysis showed that high titer (>17.5 IU/ml) IgE to any mammalian allergen had the strongest relationship with asthma at age 19 (odds ratio 5.1 [3.0-8.6]). Furthermore, IgE to mammalian allergens gave an odds ratio of 8.5 [4.9-15] for asthma that started before age 12 and was still present at age 19. Sensitization to Fel d 1 and Fel d 4 was strongly associated with asthma and significantly reduced in cat owners. Conclusions: Sensitization to cat and dog related allergens, and specifically to the components Fel d 1 and Fel d 4, is a major risk factor for the persistence and severity of asthma in an area where these are the only significant perennial allergens.

  • 24.
    Lindberg, Anne
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. the OLIN unit, Umeå University, Umeå, Sweden .
    Niska, Benjamin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine. the OLIN unit, Umeå University, Umeå, Sweden .
    Stridsman, Caroline
    Eklund, Britt-Marie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Eriksson, Berne
    Hedman, Linnéa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Low nicotine dependence and high self-efficacy can predict smoking cessation independent of the presence of chronic obstructive pulmonary disease: a three year follow up of a population-based study2015In: Tobacco Induced Diseases, ISSN 1617-9625, E-ISSN 1617-9625, Vol. 13, 27Article in journal (Refereed)
    Abstract [en]

    Background: Smoking is a major risk factor for chronic obstructive pulmonary disease (COPD), and smoking cessation is the only intervention that slows disease progression. It is important to know whether current factors related to smoking and smoking cessation are different among subjects with and without COPD in order to support smoking cessation. The aim of this study was to evaluate factors related to smoking cessation and to compare characteristics and nicotine dependence among smokers with and without COPD.

    Methods: In 2005, 1614 subjects in a population-based longitudinal study of subjects with COPD and controls were examined. The Fagerstrom Test for Nicotine Dependence (FTND) and motivation for smoking cessation were assessed for current smokers (n = 299 total, 194 with COPD). Data on smoking cessation were collected in a follow-up in 2008 (n = 240).

    Results: Smokers with COPD had more pack-years and respiratory symptoms than smokers without COPD, whereas higher FTND scores were associated with anxiety/depression and respiratory symptoms in both groups. Nineteen percent of the smokers had quit smoking by the follow-up 3 years later, and they had significantly lower FTND scores (2.54 vs. 3.75, p < 0.001) and higher self-efficacy scores (10.0 vs. 6.0, p = 0.020) at baseline than the sustained smokers. Smoking cessation was related to low FTND scores and high self-efficacy independent of the presence of COPD, respiratory symptoms, anxiety/depression, and heart disease.

    Conclusions: The FTND score and a simple visual analog scale for assessing self-efficacy seem to be valuable instruments for predicting smoking cessation over several years, independent of COPD, respiratory symptoms, presence of anxiety/depression, and heart disease.

  • 25.
    Lindberg, Anne
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sawalha, Sami
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Lars-Gunnar
    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.
    Subjects with COPD and productive cough have an increased risk for exacerbations and death2015In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 109, no 1, 88-95 p.Article in journal (Refereed)
    Abstract [en]

    Background: Chronic bronchitis is related to worse general health status, exacerbations and mortality among subjects with COPD. Also less longstanding cough and phlegm may be related to worse prognosis in COPD but this has rarely been evaluated in population-based studies. Aim: To evaluate the relationship between productive cough, exacerbations and mortality among subjects with and without COPD. Method: All subjects with COPD (n = 993) were identified together with sex-and age matched reference subjects without obstructive lung function impairment from four population-based cohorts in 2002-04. Baseline spirometry and structured interview including data on exacerbations last 12 months were used in this study (n = 1986) together with mortality data collected until February 2012. Results: Productive cough was more common in COPD than non-COPD (42.8 vs. 23.5%, p < 0.001), more common in men than women, but associated to exacerbations in both sexes. COPD-subjects with productive cough had the highest risk for exacerbations in both sexes and they had a significantly increased risk for death (HR 1.48, 95% CI 1.13-1.94) also when adjusted for sex, age, BMI, smoking habits and heart disease. Conclusion: Productive cough was common and increased the risk for exacerbations in both sexes, in both COPD and non-COPD. COPD-subjects with productive cough had the highest risk for exacerbations and a significantly higher risk for death also after adjustment for common risk factors.

  • 26.
    Rönmark, Eva
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. OLIN-studierna, Norrbottens läns landsting.
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. OLIN-studierna, Norrbottens läns landsting.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. OLIN-studierna, Norrbottens läns landsting.
    Allergier största sjukdomsgrupp hos svenska barn och unga vuxna: förekomsten av allergiska sjukdomar ökar världen över - oklart om toppen är nådd2016In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 113, no 14, 654-656 p.Article in journal (Refereed)
    Abstract [en]

    Allergic sensitization, an important risk factor for allergic diseases such as asthma and rhinitis, has increased worldwide. Almost half of the young adult population is sensitized to common airborne allergens. Parallel, the prevalence of asthma and clinical allergy also increased all over the world. Allergic diseases are the most common diseases among children, adolescents and young adults in Sweden. Among adults, 8-10% have asthma, 30% rhinitis and 11% eczema. Among children and adolescents around 5-8% report food allergy. Part of the increase in asthma prevalence is related to changes in diagnostic criteria and increased awareness in the population. The increase may have levelled off in some areas.

  • 27. Stridsman, Caroline
    et al.
    Skär, Lisa
    Hedman, Linnea
    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.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Fatigue affects health status and predicts mortality among subjects with COPD: report from the population-based OLIN COPD study2015In: COPD: Journal of Chronic Obstructive Pulmonary Disease, ISSN 1541-2555, E-ISSN 1541-2563, Vol. 12, no 2, 199-206 p.Article in journal (Refereed)
    Abstract [en]

    Background: COPD is associated to increased fatigue, decreased health status and mortality. However, these relationships are rarely evaluated in population-based studies. Aims: To describe the relationship between health status, respiratory symptoms and fatigue among subjects with and without COPD. Further, to evaluate whether fatigue and/or health status predicts mortality in these groups. Methods: Data were collected in 2007 from the population-based OLIN COPD study. Subjects participated in lung function tests and structured interviews, and 434 subjects with and 655 subjects without COPD were identified. Fatigue was assessed by FACIT-Fatigue and health status by the generic SF-36 questionnaire including physical (PCS) and mental (MCS) components. Mortality data until February 2012 were collected. Results: Fatigue greatly impacts the physical and mental dimensions of health status, both among subjects with and without COPD. Among subjects with clinically significant fatigue, COPD subjects had significantly lower PCS-scores compared to non-COPD subjects. Fairly strong correlations were found between FACIT-F, SF-36 PCS and MCS, respectively. In multivariate models adjusting for covariates, increased fatigue, decreased physical and mental dimensions of health status were all associated to mortality in subjects with COPD (OR 1.06, CI 1.02-1.10, OR 1.04, CI 1.01-1.08 and OR 1.06, CI 1.02-1.10), but not in non-COPD. Conclusions: Fatigue and decreased health status were closely related among subjects with and without COPD. Not only physical health status, but also fatigue and mental health predicted mortality among subjects with COPD. Fatigue assessed by FACIT-F, can be a useful instrument of prognostic value in the care of subjects with COPD.

  • 28.
    Strinnholm, Åsa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Winberg, Anna
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hedman, Linnéa
    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.
    Lindh, Viveca
    Umeå University, Faculty of Medicine, Department of Nursing.
    To face fear: a qualitative study of adolescents' experiences of double-blind, placebo-controlled food challenges2015In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 70, 386-386 p.Article in journal (Other academic)
    Abstract [en]

    Background: Double-blind, placebo-controlled food challenges are the gold standard for diagnosing the clinical relevance of a suspected food allergy. Hitherto there are no descriptions on how adolescents' experience this procedure. The aim of this study was to describe adolescents' experiences of double-blind, placebo-controlled food challenges and to what extent the provoked food was reintroduced following the challenge. Method: Seventeen adolescents were interviewed after participating in double-blind, placebo-controlled food challenges. The interview data was analyzed using qualitative content analysis.Results: Experiences during the challenge were: challenging fears in a secure environment, being curious but also hesitant to unknown tastes and waiting for unknown food reactions. Experiences after the challenge were: gaining control and freedom or to stay in old habits. Out of 20 challenges the outcome was negative in 11 cases and positive in 9. Five adolescents with a negative outcome and 4 with mild reactions reintroduced the provoked food. Conclusions: During the challenge the adolescents received knowledge about whether and how they reacted to the provoked food. Reintroduction of the food was not always consistent with the challenge outcome. Independent of the outcome of the challenge and the choices made based on the challenge result, all the adolescents strived for what they felt was a normal life. This study provides a better understanding of young people's experience of double-blind, placebo-controlled food challenge and their motivations to introduce -or not- the previously eliminated food. The result indicate that follow ups are important since the adolescents need support in their striving to manage new food-related situations after the challenge, independent of the outcome.

  • 29.
    Strinnholm, Åsa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Winberg, Anna
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    West, Christina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hedman, Linnea
    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.
    Food hypersensitivity is common in Swedish schoolchildren, especially oral reactions to fruit and gastrointestinal reactions to milk2014In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 103, no 12, 1290-1296 p.Article in journal (Refereed)
    Abstract [en]

    AIM: This study examined the prevalence, symptom expression and risk factors for food hypersensitivity among Swedish schoolchildren.

    METHODS: Parents of 2585 (96% of invited) children aged 7-8 years completed a questionnaire regarding food hypersensitivity and allergic diseases. A random sample of 1700 children (90% of invited) also participated in skin prick testing with ten airborne allergens.

    RESULTS: The overall prevalence of reported food hypersensitivity to milk, egg, fish, wheat, soya, fruits and, or, nuts was 21%, with symptoms caused by milk (9%) being the most common. The most frequently reported symptoms were oral symptoms (47.4%), mainly caused by fruit, and gastrointestinal symptoms (45.7%), mainly caused by milk. Factors associated with any food hypersensitivity were female sex, allergic heredity and a positive skin prick test. Eczema was consistently associated with symptoms caused by milk, egg, fish, wheat, soya, fruits and nuts. Rhinitis was associated to the same foods, except milk.

    CONCLUSION: Reported food hypersensitivity was common among Swedish schoolchildren. The most frequent symptom expressions were oral symptoms triggered by fruits and gastrointestinal symptoms triggered by milk. The high prevalence of reported symptoms should be validated by clinical examinations to provide a diagnosis.

  • 30.
    Warm, Katja
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    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.
    Lötvall, Jan
    Lundbäck, Bo
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Allergic sensitization is age-dependently associated with rhinitis, but less so with asthma2015In: Journal of Allergy and Clinical Immunology, ISSN 0091-6749, E-ISSN 1097-6825, Vol. 136, no 6, 1559-U201 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Epidemiologic data describing the association between allergic sensitization and asthma and allergic rhinitis in adults are scarce.

    OBJECTIVE: To determine the prevalence and impact of specific sensitization to airborne allergens on asthma and allergic rhinitis among adults in relation to age.

    METHODS: A random population sample (age 21-86 years) was examined with structured interview and analysis of specific IgE to 9 common airborne allergens. Of those invited, 692 (68%) subjects participated in blood sampling. IgE level of 0.35 U/mL or more to the specific allergen was defined as a positive test result.

    RESULTS: Allergic sensitization decreased with increasing age, both in the population sample and among subjects with asthma and allergic rhinitis. In a multivariate model, sensitization to animal was significantly positively associated with asthma (odds ratio [OR], 4.80; 95% CI, 2.68-8.60), whereas sensitization to both animal (OR, 3.90; 95% CI, 2.31-6.58) and pollen (OR, 4.25; 95% CI, 2.55-7.06) was significantly associated with allergic rhinitis. The association between allergic sensitization and rhinitis was consistently strongest among the youngest age group, whereas this pattern was not found for asthma. The prevalence of allergic sensitization among patients with asthma decreased by increasing age of asthma onset, 86% with asthma onset at age 6 y or less, 56% at age 7 to 19 years, and 26% with asthma onset at age 20 years or more.

    CONCLUSIONS: Sensitization to animal was associated with asthma across all age groups; allergic rhinitis was associated with sensitization to both pollen and animal and consistently stronger among younger than among older adults. Early onset of asthma was associated with allergic sensitization among adults with asthma.

  • 31.
    Warm, Katja
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Hedman, Linnéa
    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.
    Lötvall, J.
    Lundbäck, B.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Asthma is less age-dependently associated with allergic sensitization compared to rhinitis2015In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 70, 124-125 p.Article in journal (Other academic)
  • 32.
    Winberg, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Strinnholm, Åsa
    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.
    West, Christina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Perzanowski, M.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    High incidence and remission of reported food hypersensitivity in Swedish children followed from 8 to 12 years of age2014In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 69, no Supplement: 99, 151-151 p.Article in journal (Refereed)
  • 33.
    Winberg, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    West, Christina E.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Strinnholm, Åsa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Nordström, Lisbet
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hedman, Linnéa
    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.
    Assessment of allergy to cow's milk, hen's egg, cod, and wheat in a population-based cohort of Swedish schoolchildren2015In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 70, 266-267 p.Article in journal (Other academic)
  • 34.
    Winberg, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    West, Christina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Strinnholm, Åsa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nordström, Lisbeth
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hedman, Linnea
    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.
    Milk allergy is a minor cause of milk avoidance due to perceived hypersensitivity among schoolchildren in Northern Sweden2016In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 105, no 2, 206-214 p.Article in journal (Refereed)
    Abstract [en]

    AIM: We investigated phenotypes of milk hypersensitivity among schoolchildren aged 11-12 in Northern Sweden.

    METHODS: In a population-based cohort, 1,824 (98%) children aged 11-12 participated in a questionnaire survey, skin prick testing, interviews on food hypersensitivity and assessment of body mass index (BMI). Of the 265 children reporting milk hypersensitivity, milk avoidance and no celiac disease, 236 (89%) participated in a structured interview and blood samples for analyses of milk-specific Immunoglobulin E. The children were then categorised into milk hypersensitivity phenotypes according to preset criteria.

    RESULTS: In all, 14.5% reported milk hypersensitivity. Of these, 3% were categorised as current milk allergy, 23% as outgrown milk allergy, 40% as probable lactose intolerance and 11% were non-definable. Furthermore, 23% had discontinued their elimination diet. Milk allergy was associated with other atopic disorders and lower BMI, with an odds Ratio of 0.82 and 95% confidence interval of 0.80-0.98. Only 2% had previously undergone an oral challenge.

    CONCLUSION: The most common symptom phenotypes among Swedish children aged 11-12 with self-reported milk hypersensitivity and milk avoidance, were lactose intolerance and outgrown milk allergy while current milk allergy was uncommon. Children with milk allergy had a lower BMI and most lacked a challenge proven diagnosis. 

1 - 34 of 34
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