Risk factors and prevalence of asthma or atopic dermatitis in young children by a questionnaire survey.

Little is known about the relation between atopic disorders and altitude of residence. The author investigated the prevalence of asthma and atopic dermatitis, and their relationship with altitude of residence. A total of 24,631 children aged four years and under in Gunma Prefecture, Japan, were surveyed. The ATS-DLD questionnaire for asthma was distributed together with an item on atopic dermatitis. Some confounding variables were also asked. The author judged subjects as having asthma when positive answers were given to all 6 items in the ATS/DLD questionnaire. The prevalence of asthma in subjects with atopic dermatitis was higher than in those without (5.1% vs. 1.8%). Logistic regression analyses for asthma and atopic dermatitis were conducted, and male sex, increasing age, family history of target disease, and living at higher altitude commonly and significantly contributed to an increase in the risk of each allergic disorder. For asthma, not being the eldest child, and past or present history of atopic dermatitis were also selected as risk factors. There was an increase in the prevalence of atopic disorders in groups living at a higher altitude was observed in this area.