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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.
    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, 859-866 p.Article 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.

  • 2.
    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.

  • 3.
    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)
  • 4. 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, AB22-AB22 p.Article 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.

  • 5. Bjerg, Anders
    et al.
    Ekerljung, Linda
    Eriksson, Jonas
    Olafsdóttir, Inga Sif
    Middelveld, Roelinde
    Franklin, Karl A.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Kjell
    Lötvall, Jan
    Torén, Kjell
    Dahlén, Sven-Erik
    Lundbäck, Bo
    Janson, Christer
    Higher risk of wheeze in female than male smokers: results from the Swedish GA(2)LEN study2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 1, e54137Article in journal (Refereed)
    Abstract [en]

    Background: Women who smoke have higher risk of lung function impairment, COPD and lung cancer than smoking men. An influence of sex hormones has been demonstrated, but the mechanisms are unclear and the associations often subject to confounding. This was a study of wheeze in relation to smoking and sex with adjustment for important confounders.

    Methods: In 2008 the Global Allergy and Asthma European Network (GA2LEN) questionnaire was mailed to 45.000 Swedes (age 16–75 years), and 26.851 (60%) participated. “Any wheeze”: any wheeze during the last 12 months. “Asthmatic wheeze”: wheeze with breathlessness apart from colds.

    Results: Any wheeze and asthmatic wheeze was reported by 17.3% and 7.1% of women, vs. 15.8% and 6.1% of men (both p<0.001). Although smoking prevalence was similar in both sexes, men had greater cumulative exposure, 16.2 pack-years vs. 12.8 in women (p<0.001). Most other exposures and characteristics associated with wheeze were significantly overrepresented in men. Adjusted for these potential confounders and pack-years, current smoking was a stronger risk factor for any wheeze in women aged <53 years, adjusted odds ratio (aOR) 1.85 (1.56–2.19) vs. 1.60 (1.30–1.96) in men. Cumulative smoke exposure and current smoking each interacted significantly with female sex, aOR 1.02 per pack-year (p<0.01) and aOR 1.28 (p = 0.04) respectively. Female compared to male current smokers also had greater risk of asthmatic wheeze, aOR 1.53 vs. 1.03, interaction aOR 1.52 (p = 0.02). These interactions were not seen in age ≥53 years.

    Discussion: In addition to the increased risk of COPD and lung cancer female, compared to male, smokers are at greater risk of significant wheezing symptoms in younger age. This became clearer after adjustment for important confounders including cumulative smoke exposure. Estrogen has previously been shown to increase the bioactivation of several compounds in tobacco smoke, which may enhance smoke-induced airway inflammation in fertile women.

  • 6.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Ekerljung, Linda
    Middelveld, Roelinde
    Dahlén, Sven-Erik
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Franklin, Karl
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Larsson, Kjell
    Lötvall, Jan
    Ólafsdóttir, Inga Sif
    Torén, Kjell
    Lundbäck, Bo
    Janson, Christer
    Increased prevalence of symptoms of rhinitis but not of asthma between 1990 and 2008 in Swedish adults: comparisons of the ECRHS and GA2LEN surveys2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 2, e16082- p.Article in journal (Refereed)
    Abstract [en]

    Background

    The increase in asthma prevalence until 1990 has been well described. Thereafter, time trends are poorly known, due to the low number of high quality studies. The preferred method for studying time trends in prevalence is repeated surveys of similar populations. This study aimed to compare the prevalence of asthma symptoms and their major determinants, rhinitis and smoking, in Swedish young adults in 1990 and 2008.

    Methods

    In 1990 the European Community Respiratory Health Survey (ECRHS) studied respiratory symptoms, asthma, rhinitis and smoking in a population-based sample (86% participation) in Sweden. In 2008 the same symptom questions were included in the Global Allergy and Asthma European Network (GA2LEN) survey (60% participation). Smoking questions were however differently worded. The regions (Gothenburg, Uppsala, Umeå) and age interval (20–44 years) surveyed both in 1990 (n = 8,982) and 2008 (n = 9,156) were analysed.

    Results

    The prevalence of any wheeze last 12 months decreased from 20% to 16% (p<0.001), and the prevalence of “asthma-related symptoms” was unchanged at 7%. However, either having asthma attacks or using asthma medications increased from 6% to 8% (p<0.001), and their major risk factor, rhinitis, increased from 22% to 31%. Past and present smoking decreased.

    Conclusion

    From 1990 to 2008 the prevalence of obstructive airway symptoms common in asthma did not increase in Swedish young adults. This supports the few available international findings suggesting the previous upward trend in asthma has recently reached a plateau. The fact that wheeze did not increase despite the significant increment in rhinitis, may at least in part be due to the decrease in smoking.

  • 7. Bjerg, Anders
    et al.
    Eriksson, Jonas
    Ólafsdóttir, Inga Sif
    Middelveld, Roelinde
    Franklin, Karl
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Kjell
    Torén, Kjell
    Dahlén, Sven-Erik
    Janson, Christer
    The association between asthma and rhinitis is stable over time despite diverging trends in prevalence2015In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 109, no 3, 312-9 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Despite the well-known association between asthma and rhinitis, in Swedish adults the prevalence of rhinitis rose from 22% to 31% between 1990 and 2008 while asthma prevalence was unchanged. We tested whether the association of rhinitis with asthma was stable over time using the same population-based databases.

    METHODS: Two surveys of adults (20-44 years) living in three regions of Sweden, carried out in 1990 (n = 8982) and 2008 (n = 9156) were compared. Identical questions regarding respiratory symptoms, asthma and rhinitis were used. Asthmatic wheeze: Wheeze with breathlessness apart from colds. Current asthma: Asthma attacks and/or asthma medication use.

    RESULTS: Subjects with rhinitis had level time trends in asthmatic wheeze, current asthma and most nocturnal respiratory symptoms between 1990 and 2008, adjusted for age, sex, area and smoking. Any wheeze however decreased slightly. In never-smokers asthma symptoms were similarly associated with rhinitis in 1990 and 2008: any wheeze OR 4.0 vs. 4.4 (p = 0.339); asthmatic wheeze OR 6.0 vs. 5.9 (p = 0.937); and current asthma OR 9.6 vs. 7.7 (p = 0.213). In the whole population there were decreases in the asthma symptoms most closely associated to smoking, which decreased by half 1990-2008. Conversely current asthma, which was strongly associated with rhinitis and not with smoking, increased (p < 0.001).

    CONCLUSIONS: The association of rhinitis with asthma was stable between 1990 and 2008. The pattern in the time trends of asthma outcomes strongly suggests that decreased smoking counterbalanced the driving effect of increased rhinitis on asthma prevalence. The findings illustrate the public health benefits of decreased smoking.

  • 8. 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.

  • 9.
    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.

  • 10.
    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.

  • 11.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lundbäck, Bo
    Platts-Mills, Thomas
    Perzanowski, Matthew
    Rönmark, Eva
    Changes in the risk factor pattern of childhood asthma from 1996 to 2006Manuscript (Other academic)
  • 12.
    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, 123-126 p.Article 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.

  • 13.
    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, 48-55 p.Article 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.

  • 14.
    Bjerg, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Sandström, Thomas
    Lundbäck, Bo
    Rönmark, Eva
    Sex-specific trends in childhood asthma and wheeze: prevalence and risk factors in Sweden 1996-2006Manuscript (Other academic)
  • 15.
    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, 557-563 p.Article 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.

  • 16.
    Bjerg Bäcklund, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Epidemiology of asthma in primary school children: the Obstructive Lung Disease in Northern Sweden (OLIN) studies thesis VIII2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Childhood asthma has increased worldwide, although recent studies report a prevalence plateau in some western countries.

    Aims: To investigate the prevalence of asthma and the associated risk factor patterns from ages 7-8 to 11-12 with special emphasis on the hereditary component, and further to study prevalence trends at age 7-8 from 1996 to 2006 and the possible determinants of these trends.

    Methods: The studies involved two cohorts from Kiruna, Luleå and Piteå: one previously identified cohort of 3430 children age 7-8 followed by yearly questionnaires until age 11-12 with 97% yearly participation. Skin-prick tests for allergic sensitisation were performed at ages 7-8 and 11-12 in subsets of 2148 and 2155 children respectively (88% of invited). In 2006 a new cohort of 7-8-year-olds was identified and examined identically. 2585 (96% of invited) and 1700 (90% of invited) participated in the questionnaire and skin-prick tests, respectively. The questionnaire included questions about symptoms of asthma, allergic rhinitis and eczema, and possible risk factors.

    Results: In the 1996 cohort, 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), and 34.7% reported ever wheee at ≥one occasion. Remission was 10% of which half relapsed during the study. Remission was significantly lower among sensitised children. The strongest risk factors for current asthma at ages 7-8 and 11-12 were allergic sensitisation (OR 5) and family history of asthma (OR 3). Several other significant risk factors, e.g. respiratory infections, damp house and low birth weight, had lost importance at age 11-12. At age 7-8, parental asthma was a stronger risk factor (OR 3-4) than parental rhinitis or eczema (OR 1.5-2). Sibling asthma had no independent effect. Biparental asthma had a multiplicative effect (OR 10). Maternal and paternal asthma was equally important, regardless of the child’s sex and sensitisation status.

    From 1996 to 2006 the prevalence of current wheeze and asthma at age 7-8 did not increase (P=0.13, P=0.18), while lifetime prevalence of ever wheeze and physician-diagnosed asthma increased (P<0.01, P=0.01). Symptoms of rhinitis and eczema were unchanged, despite 45% increase (P<0.01) in allergic sensitisation. For current asthma the adjusted population attributable fractions of sensitisation and parental asthma increased (35%-41%, 27%-45%). This was however balanced by decreased exposure to infections, maternal smoking and home dampness, resulting in stable asthma prevalence. Stratification by sex revealed that current wheeze increased in boys (P<0.01) but tended to decrease in girls (P=0.37), seemingly due to symptom persistence in males. Several asthma indices followed this pattern. The boy-to-girl ratio in exposure to all studied risk factors increased, which may explain the sex-specific prevalence trends in wheeze.

    Conclusions: The prevalence of current asthma and wheeze did not increase statistically significantly. However, the risk factor pattern has changed considerably since 1996, which will presumably affect the clinical features of childhood wheeze in this region. Sex-specific trends in wheeze can be explained by changes in exposure, and trends in risk factors should be explored parallel to prevalence trends.

  • 17.
    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, 549-55 p.Article in journal (Refereed)
  • 18. Ekerljung, Linda
    et al.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Kjell
    Sundblad, Britt-Marie
    Bjerg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Ahlstedt, Staffan
    Dahlén, Sven-Erik
    Lundbäck, Bo
    No further increase of incidence of asthma: incidence, remission and relapse of adult asthma in Sweden.2008In: Respiratory medicine, ISSN 1532-3064, Vol. 102, no 12, 1730-6 p.Article 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.

  • 19. 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, 1611-1621 p.Article 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.

  • 20. 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, 211-219 p.Article 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.

  • 21. 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.

  • 22. Hagstad, Stig
    et al.
    Bjerg, Anders
    Ekerljung, Linda
    Backman, Helena
    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. Obstructive Lung Disease In Northern Sweden (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. Obstructive Lung Disease In Northern Sweden (OLIN) studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå.
    Lundbäck, Bo
    Passive smoking exposure is associated with increased risk of COPD in never-smokers2014In: Chest, ISSN 0012-3692, E-ISSN 1931-3543, Vol. 145, no 6, 1298-1304 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND Passive smoking, or environmental tobacco smoke (ETS), is a risk factor for lung cancer, cardiovascular disease and childhood asthma, but a relationship with COPD has not been fully established.

    AIM To study ETS as a risk factor for COPD in never-smokers.

    METHODS Data from three cross-sectional studies within the Obstructive Lung Disesease in Northern Sweden (OLIN) database were pooled. Of the 2182 lifelong never-smokers 2118 completed structured interviews and spirometry of acceptable quality. COPD was defined according to the GOLD criteria using post-bronchodilator spirometry. The association of COPD with ETS in single and multiple settings was calculated by multivariate logistic regression adjusting for known risk factors for COPD.

    RESULTS COPD prevalence was associated with increased ETS exposure: 4.2% (no ETS), 8.0% (ETS ever at home), 8.3% (ETS at previous work) and 14.7% (ETS ever at home and at both previous and current work), test for trend p=0.003. Exclusion of subjects aged ≥65 years and subjects reporting asthma yielded similar results. ETS in multiple settings, such as ever at home and at both previous and current work was strongly associated to COPD, OR 3.80 (95% CI 1.29-11.2).

    CONCLUSIONS In this population-based sample of never-smokers, ETS was independently associated with COPD. The association was stronger for ETS in multiple settings. ETS in multiple settings was, after age, the strongest risk factor for COPD and comparable to personal smoking of up to 14 cigarettes/day in comparable materials. The findings strongly advocate measures against smoking in public places.

  • 23.
    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.

  • 24.
    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)
  • 25.
    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.

  • 26.
    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.

  • 27.
    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.

  • 28.
    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.

  • 29. 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.

  • 30. Jerning, Camilla
    et al.
    Martinander, Emma
    Bjerg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Ekerljung, Linda
    Franklin, Karl
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Järvholm, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Kjell
    Malinovschi, Andrei
    Middelveld, Roelinde
    Emtner, Margareta
    Janson, Christer
    Asthma and physical activity: a population based study results from the Swedish GA(2)LEN survey2013In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 107, no 11, 1651-1658 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Having asthma has in previous reports been related to a lower physical activity level. At the same time the prevalence of asthma among elite athletes is high. The aim of this study was to investigate the association between physical activity level and asthma.

    METHODS: A postal questionnaire was completed by 25,610 individuals in Sweden. Current asthma was defined as having had an asthma attack during the last 12 months or current use of asthma medication. The participants were asked how often and for how many hours a week they were physically active.

    RESULTS: In the population 1830 subjects (7.1%) had current asthma. There was no significant difference in the proportion of subjects that reported being inactive or slightly physically active between asthmatic and non-asthmatics (57 vs. 58%) while the proportion of subjects that were vigorously physically active (≥2 times a week and ≥7 h per week) was higher among the subjects with asthma (6.7 vs. 4.8%, p < 0.0001). Being vigorously physically active was independently related to current asthma (OR (95% CI)) 1.40 (1.11-1.77)), wheeze (1.39 (1.17-1.65)), wheeze and breathlessness (1.68 (1.38-2.04)), and wheezing without having a cold (1.39 (1.13-1.71)). The association between being vigorously physically active and wheeze was significantly stronger in women compared to men.

    CONCLUSIONS: There was no difference in the proportion of subjects with a reported low level of physical activity between asthmatics and non-asthmatics. Health care professionals should, however, be aware of the increased prevalence of asthma and asthma-related symptoms in vigorously physically active subjects.

  • 31.
    Lindberg, Anne
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Bjerg Bäcklund, Anders
    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.
    Larsson, Lars-Gunnar
    Lundbäck, Bo
    Prevalence and underdiagnosis of COPD by disease severity and the attributable fraction of smoking Report from the Obstructive Lung Disease in Northern Sweden Studies.2006In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 100, no 2, 264-272 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: There is a lack of epidemiological data on COPD by disease severity. We have estimated the prevalence and underdiagnosis of COPD by disease severity defined by the British Thoracic Society (BTS) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. The impact of smoking was evaluated by the population attributable fraction of smoking in COPD. METHODS: A random sample of 1500 responders of the third postal survey performed in 1996 of the Obstructive Lung Disease in Northern Sweden (OLIN) Studies' first cohort (6610 subjects recruited in 1985) were invited to structured interview and spirometry. One thousand two hundred and thirty-seven subjects (82%) performed spirometry. RESULTS: The prevalence of mild BTS-COPD was 5.3%, moderate 2.2%, and severe 0.6% (GOLD-COPD: mild 8.2%, moderate 5.3%, severe 0.7%, and very severe 0.1%). All subjects with severe COPD were symptomatic, corresponding figures among mild COPD were 88% and 70% (BTS and GOLD), Subjects with severe BTS-COPD reported a physician-diagnosis consistent with COPD in 50% of cases, in mild BTS-COPD 19%, while in mild GOLD-COPD only 5% of cases. The major risk factors, age and smoking, had a synergistic effect on the COPD-prevalence. The Odds Ratio (OR) for having COPD among smokers aged 76-77 years was 59 and 34 (BTS and GOLD) when non-smokers aged 46-47 was used as reference population. CONCLUSIONS: Most subjects with COPD have a mild disease. The underdiagnosis is related to disease-severity. Though being symptomatic, only a half of the subjects with severe COPD are properly labelled. Smoking and increasing age were the major risk factors and acted synergistic.

  • 32. Lâm, Hoàng Thị
    et al.
    Ekerljung, Linda
    Bjerg, Anders
    Văn T Tng, Nguyễn
    Lundbäck, Bo
    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 .
    Sensitization to airborne allergens among adults and its impact on allergic symptoms: a population survey in northern Vietnam2014In: Clinical and Translational Allergy, ISSN 2045-7022, E-ISSN 2045-7022, Vol. 4, no 1, 6- p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The knowledge about allergic sensitization and its relationship with clinical symptoms and diseases among adults in South-East Asia is poor. The aim of this study was to investigate the prevalence and pattern of allergic sensitization and the association with asthma and allergic rhinitis in adults in urban and rural Vietnam. METHODS: Among 5,782 responders to a questionnaire survey in northern Vietnam, a random sample was invited to a clinical follow-up and 684 (46%) participated. The methods included a structured interview using a modified GA2LEN study questionnaire on symptoms and possible determinants for diseases. Skin prick test (SPT) with ten common airborne indoor and outdoor allergens, lung function test, and methacholine test was performed among subjects ≤60 years of age. RESULTS: In total, one third of subjects had a positive SPT reaction to at least one allergen, 36.9% of men and 31.0% of women (n.s.). The most common sensitizer was the storage mite B. tropicalis (men 27.7%; women 18.7%) followed by house dust mite D. pteronyssinus (men 16.5%; women 10.6%), and D. farinae (men 15.3%; women 6.3%), and cockroach (men 16.5%; women 10.2%). Sensitization to all major allergens were significantly more common among men and among subjects ≤45 years compared with women and subjects >45 years, respectively. The prevalence of sensitization to animals, pollen and molds were low. The majority of cockroach-sensitized subjects were also sensitized to mites. Sensitization to any allergen and all major allergens were significantly associated with rhinitis, but not with asthma. However, bronchial hyper-reactivity was significantly associated with increasing number of positive SPTs (p = 0.047). CONCLUSIONS: Among adults in northern Vietnam sensitization to mite and cockroach most common in both rural and urban areas. The dominant sensitizer was the storage mite B. tropicalis, which should be included in future studies and also in clinical practice, owing to its association with clinical symptoms. As in the Western world allergic sensitization was associated with rhinitis and bronchial hyper-reactivity. The lack of association with asthma in South-East Asia needs to be studied further.

  • 33.
    Rönmark, Eva
    et al.
    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, Sweden.
    Bjerg, Anders
    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, Sweden.
    Hedman, L
    Perzanowski, M
    Sundberg, S
    Lundbäck, B
    The Obstructive Lung Disease in Northern Sweden (OLIN) longitudinal paediatric study I: the first 10 years2008In: Clinical Respiratory Journal, ISSN 1752-6981, E-ISSN 1752-699X, Vol. 2, no Suppl 1, 26-33 p.Article in journal (Refereed)
    Abstract [en]

    Background: Prospective studies of asthma and allergic conditions based oil the general population are scare.

    Aim: To summarize the methods and main results from a prospective study among school children.

    Methods: In 1996, a cohort of 3525 children aged 7/8 years in Northern Sweden were invited to a questionnaire survey using an expanded ISAAC protocol, and 97% participated. The cohort has been followed up yearly with high participation rate. Skin prick tests were conducted 1996, 2000 and 2006/2007. Allergens in dust from homes and schools have been analyzed. Sub samples have participated in interviews, lung function tests, bronchial hyper reactivity test, and analyses of IgE and IgG antibodies in serum.

    Results: The prevalence of asthma was 6% at age 7-8 years and increased by age. The incidence of physician-diagnosed asthma after the age of 7-8 years was around 1/100/year. The prevalence of positive skin prick test increased from 21% at age 7-8 to 30% at age 11-12 years. Remission of allergic sensitization was rare, while asthma remission was 5% yearly. The main risk factor for asthma and allergic sensitization increased in importance with increasing age. Allergic and non-allergic asthma had different risk factor pattern. Environmental risk factors decreased in impact after the age of 7. Avoidance of pets at home did not protect from asthma or allergic sensitization.

    Conclusion: The study includes important sources of data for further longitudinal analyses that will contribute to the understanding of the development and the nature of asthma and allergic sensitization.

  • 34.
    Rönmark, Eva
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bjerg, Anders
    Perzanowski, Matthew
    Platts-Mills, Thomas
    Lundbäck, Bo
    Major increase in allergic sensitization in schoolchildren from 1996 to 2006 in northern Sweden.2009In: The Journal of allergy and clinical immunology, ISSN 1097-6825, Vol. 124, no 2, 357-63, 63.e1 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Time trends for allergic sensitization are poorly known. OBJECTIVE: To compare the trends in prevalence of allergic sensitization and associated risk factors in children. METHODS: Two cohorts of children (age 7-8 years) were invited for skin prick tests (SPTs) 10 years apart, 1996 and 2006. The participation rates were 2148 (88%) and 1700 (90%), respectively. The methods were identical, and 10 common airborne allergens were used. An expanded International Study of Allergy and Asthma in Children questionnaire about symptoms and possible risk factors for allergic conditions was completed by the parents. RESULTS: The prevalence of any positive SPT increased from 21% in 1996 to 30% in 2006 (P < .001). The pattern of sensitization remained similar, and sensitization to cat was most common both years, 13% and 19%, respectively. Sensitization to mites and mold was uncommon in both surveys. A family history of allergy was a significant risk factor for a positive SPT both years (odds ratio, 1.7). Factors that in 1996 had a protective effect, such as rural living and having several siblings, had lost this effect in 2006. The prevalence of most risk factors remained similar, but respiratory infections and smoking among parents decreased significantly. During the same period, there was no significant increase in the prevalence of current wheeze (11.9% to 12.4%, P = .636) or symptoms of rhinitis or eczema. CONCLUSION: The prevalence of allergic sensitization increased significantly from 1996 to 2006, whereas no increase in clinical symptoms was found. The parallel decrease in parental smoking and respiratory infections indicate a different influence of environmental factors on allergic sensitization and clinical symptoms, respectively.

  • 35. Sjölander, Sigrid
    et al.
    Bjerg, Anders
    Ekerljung, Linda
    Bengtsson-Gref, Otti
    Borres, Magnus
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lötvall, Jan
    Lundbäck, Bo
    IgE to Furry Animal Allergen Components Was Associated with Asthma in a Population-Based Study of Adults2015In: 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]

    Atopic sensitization increases the risk of asthma. Our aim was to investigate patterns of sensitization to allergens and allergen components in relation to asthma among adults in a Swedish population-based sample. Methods: A questionnaire targeting asthma was sent to 30 000 randomly selected adults (16-75 y) in west Sweden. Of the 18 087 responders, a randomly selected sample of 2000 subjects and in addition all 1536 subjects reporting asthma were invited to clinical examinations. Sera were received from 906 subjects with asthma and from 1000 without reported asthma (controls) and were tested for three IgE panels of inhalant and food allergens. Samples with a level of IgE >0.35 kUA/l were further analyzed for IgE against each individual allergen and nine allergen components related to furry animals. Results: The risk of being sensitized to any of the 21 tested allergens was significantly higher in the asthma group. The risk was highest for individuals sensitized to furry animals (risk ratios 4,5-7,9). The level of IgE to animal allergens was also significantly higher in the asthma group. Co-sensitization to more than one cat and/or dog allergen component conferred a greater risk for asthma. Simultaneous sensitization to the cat allergens Fel d 1 and Fel d 4 was associated with asthma. Conclusions: In this large population-based study subjects with asthma were commonly co-sensitized to more than one animal allergen component, especially to Fel d 1 and Fel d 4. Component-resolved analysis has the potential to increase precision when assessing asthma in adults.

  • 36.
    Sommar, Johan Nilsson
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Ek, Alexandra
    Middelveld, Roelinde
    Bjerg, Anders
    Dahlén, Sven-Erik
    Janson, Christer
    Forsberg, Bertil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Quality of life in relation to the traffic pollution indicators NO2 and NOx: results from the Swedish GA2LEN survey2014In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 1, e000039- p.Article in journal (Refereed)
    Abstract [en]

    Background Asthma is a chronic disease that may affect daily activities and quality of life. Asthmatics have higher incidence of chronic rhinosinusitis (CRS) and asthma is associated with sinonasal inflammation and nasal symptoms, that all impair quality of life. Worsening of asthma has been found associated with levels of nitrogen dioxide as traffic indicator.

    Aims The aim of the study was to evaluate the impact of traffic pollution indicated by nitrogen oxides (NO2 and NOx) on quality of life in asthmatic persons, individuals with CRS and controls.

    Methods Within the Swedish Ga2len (Global Allergy and Asthma European Network), 605 asthmatics with and without CRS, 110 individuals with CRS only and 226 controls from four cities were surveyed. The mini Asthma Quality of life Questionnaire (mAQLQ) and the Euro Quality of Life (EQ-5D) health questionnaire were used. Air pollution concentrations at the home address were modelled using dispersion models.

    Results Levels of NO2 (geometric mean 10.1 μg/m3 (95% CI 9.80 to 10.5) and NOx (12.1 μg/m3, 11.7 to 12.6) were similar among conditions (controls, asthmatics, individuals with CRS and asthmatics with CRS). The mAQLQ overall score was not found associated with levels of NO2 or NOx, with or without adjustments, and neither was scores within each of the four domains of mAQLQ: symptoms, activity limitations, emotional functions and effects of environmental stimuli. The mean EQ-5D index value, based on the five dimensions mobility, self-care, usual activities, pain/discomfort and anxiety depression, was also found unrelated to NO2 and NOx.

    Conclusions At moderate exposure levels traffic pollution appears not to affect quality of life.

1 - 36 of 36
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