Risk factors determining allergic airway diseases in Turkish subjects.

With regard to changes in life-style after the 1980s, the reflection of environmental factors on the evolution of allergic airway disease (AAD) has not yet been analyzed in Turkey. In this trial, we aimed to determine the factors related to AAD in Turkish subjects. Patients diagnosed as having asthma and/or rhinitis with positive skin prick tests (SPTs) were accepted as members of the "atopic group" (n = 235). Subjects demonstrated to have negative SPTs and no clinical evidence of any atopic disorder were accepted as members of the "nonatopic control group" (n = 84). Data obtained from a questionnaire applied cross-sectionally to the study groups were compared for risk factor analysis. According to the results of univariate analysis, nonatopic controls were found to have been born in villages more frequently than those in the atopic group (14.3% vs. 4.7%, p = 0.02). Atopic group members had lived in apartments during childhood more frequently than nonatopic controls (53.6% vs. 38%, p = 0.04). A topic group members, particularly the asthmatics, had lower sibship size (< or = 1 sibling) (41.3% vs. 16.7%, p = 0.0003) and nonatopic subjects had higher sibship size (> or = 3 siblings) (73.8% vs. 43.4%, p < 0.0001). The rate of maternal atopy was higher in the atopic group (24.7% vs. 9.5%, p = 0.02). Place of birth, sibship size, and atopic status of the mother, but not house type, were found to be significant in the multivariate analysis. As a conclusion, rural life-style seems to have a protective effect on the development of atopy in Turkey. On the contrary, factors directly or indirectly related to urban life-style during early childhood were found to be associated with the allergic airway diseases.