Different pattern of risk factors for atopic and nonatopic asthma among children--report from the Obstructive Lung Disease in Northern Sweden Study

Allergy. 1999 Sep;54(9):926-35. doi: 10.1034/j.1398-9995.1999.00044.x.


Background: A cross-sectional study was performed among 78-year-old schoolchildren during the winter of 1996 in three municipalities in the most northern province of Sweden, Norrbotten. The study was the starting point of a longitudinal study of asthma, rhinitis, eczema, and type-1 allergy, and provided data on prevalence and risk factors for these conditions. The aim of the present study was to validate the classification of asthma based on a parental questionnaire, and to examine risk factors for atopic and nonatopic asthma.

Methods: The ISAAC questionnaire with additional questions was distributed by the schools to the parents. The response rate was 97%, and 3431 completed questionnaires were returned. The children in Kiruna and Luleå were also invited to be skin tested, and 2149 (88%) were tested with 10 common airborne allergens. A structured interview was administered by pediatricians in stratified samples of the children to test the validity of the diagnosis of asthma based on the questionnaire.

Results: After the validation study, the prevalence of "ever asthma" was estimated to be 8.0%. The specificity of the question, "Has your child been diagnosed as having asthma by a physician?", was high, >99%, while the sensitivity was around 70%. The strongest risk factor for "ever asthma" was a positive skin test (OR 3.9). Risk factors for asthma in the asthmatics who were not sensitized were family history of asthma, OR 3.6; breast-feeding less than 3 months, OR 1.8; past or present dampness at home, OR 1.8; smoking mother, OR 1.7; and male sex, OR 1.6. Among the sensitized asthmatics, only a family history of asthma was a significant risk factor (OR 3.0), while breast-feeding less than 3 months was not associated with an increased risk (OR 1.0). A synergistic effect between genetic and environmental factors was found especially in the nonatopic asthmatics; the children with a family history of asthma who had a smoking mother and past or present dampness at home had an OR for "ever asthma" of 13.

Conclusions: Different risk-factor patterns were found for asthma and type-1 allergy. In addition, the risk factors for atopic or allergic asthma diverged from those for nonatopic asthma.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Asthma / classification
  • Asthma / epidemiology
  • Asthma / etiology*
  • Asthma / genetics
  • Child
  • Cross-Sectional Studies
  • Female
  • Humans
  • Humidity / adverse effects
  • Hypersensitivity / complications*
  • Male
  • Parents
  • Risk Factors
  • Surveys and Questionnaires
  • Sweden
  • Tobacco Smoke Pollution / adverse effects


  • Tobacco Smoke Pollution