Allergy in day care children: prevalence and environmental risk factors.

Aim: To investigate the prevalence of atopic disease among Finnish day care children and the relationship between atopy and environmental factors.

Methods: A cross-sectional study of 594 day care children aged 1-6 years from Helsinki, Finland. Each child's history of atopic diseases and environmental exposure was collected in a questionnaire completed by the parents.

Results: The prevalence of diagnosed asthma was 0.9% for the 1-3-year olds and 5.5% for the 4-6-year olds, atopic eczema/dermatis was 16% in both groups, and allergic rhinitis 5% in the younger group, 9% in the older group. According to multivariable logistic regression models, breastfeeding (exclusive > or =4 months or partial > or =6 months) reduced the risk of atopic diseases (OR = 0.60; CI(95) 0.39-0.93, p = 0.021). Atopic diseases were more common in the oldest age group, 5-6-year olds, compared to the youngest, 1-2-year olds (OR = 2.18; CI(95) 1.14-4.15, p = 0.018). One parent with atopic disease increased the child's risk (OR = 1.89; CI(95) 1.20-2.97, p = 0.006), more so if both parents had a history (OR = 3.17; CI(95) 1.48-6.78, p = 0.003).

Conclusion: Our results support the hypothesis that breastfeeding for at least six months may protect against atopic diseases. The child's greater age (5-6 years) and parental history of atopic diseases increased the risk of atopy.