Factors related to allergic sensitization to aeroallergens in a cross-sectional study in adults: The Copenhagen Allergy Study

Background The factors underlying recent increases in the prevalence of res piratory allergy are largely unknown. Objective To assess the association between allergic sensitization and seve ral lifestyle/environmental factors. Methods A cross-sectional population-based study of 15-69-year-olds in Cope nhagen was carried out in 1990. The participation rate was 77.5% (1112/1435 ). Different lifestyle/ environmental factors (explanatory variables) were defined based on questionnaire data. Dependent (outcome) variables were ski n prick test (SPT) positivity or specific IgE positivity to common aeroalle rgens. Explanatory variables associated with outcome in univariate analysis (P < 0.25) were selected for multivariate analysis. Subsequently, a final model for each dependent variable was obtained by stepwise regression analy sis (cutoff for entry/removal of variables: P < 0.1). Results Male sex, young age, low number of siblings, a positive family hist ory of hay fever and never smoking, were independently associated with both SPT positivity and specific IgE positivity. Furthermore, SPT positivity wa s positively associated with alcohol consumption (dose-response relationshi p only), and negatively associated with previous keeping of a dog in the ho usehold. The association between alcohol consumption and SPT positivity was mainly due to the consumption of wine and remained after adjustment for ed ucational level. Specific IgE positivity was furthermore associated with bo dy mass index with no apparent dose-response relationship. Conclusion Being mate, young age, a positive family history of hayfever, lo w number of siblings and never smoking, were independently associated with allergic sensitization. In addition, the results indicated a possible relat ionship of alcohol consumption, body mass index and previous keeping of a d og in the household to allergic sensitization. There is a need for prospect ive studies of risk factors for respiratory allergy.