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 ≥4 months or partial ≥6 months) reduced the risk of atopic diseases (OR = 0.60; CI₉₅ 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; CI₉₅ 1.14–4.15, p = 0.018). One parent with atopic disease increased the child's risk (OR = 1.89; CI₉₅ 1.20–2.97, p = 0.006), more so if both parents had a history (OR = 3.17; CI₉₅ 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.