Background: The reported impact of day-care attendance on respiratory and atopic symptoms has varied between studies from different countries. Regarding to the ‘hygiene-hypothesis’, day-care attendance may lead to less sensitization later in life, but the question still is whether day-care attendance and subsequent exposure to more frequent early infections is a risk or a protection against future allergic disease or asthma (atopic and nonatopic).
Methods: A cross-sectional postal questionnaire was replied by parents of 10 851 children, aged 1–6 years, in the year 2000 in a Swedish region (DBH-phase 1). The questionnaire focused on respiratory and atopic symptoms, the home environment and information on day care of the children.
Results: Children in day care were reported to have more symptoms than children in home care: adjusted odds ratio (AOR) for wheezing last 12 months, AOR 1.33 (CI 95%: 1.12–1.58), cough at night apart from colds last 12 months AOR 1.56 (CI: 1.17–2.07), doctor diagnosed asthma AOR 1.23 (CI: 0.88–1.71), rhinitis last 12 months AOR 1.15 (CI: 0.92–1.44), doctor diagnosed hay fever AOR 1.75 (CI: 0.94–3.23), eczema last 12 months, AOR 1.49 (CI: 1.24–1.79), allergic reactions to foods, AOR 1.27 (CI: 1.07–1.52), >6 colds last 12 months of 2.57 (CI: 2.12–3.12) and ear infection ever AOR 2.14 (CI: 1.87–2.45). The increased risks were mainly seen and reached significance in the youngest group of children, aged 1–4 years. Adjusting and stratification for the number of airway infections last year did not change the risk associated with day-care attendance for allergic diseases.
Conclusions: Attending day care was associated with an increased risk of symptoms related to airways infections as well with eczema and allergic reactions to food. No sign of protection from day-care attendance for allergic diseases was found up to 6 years of age. Multiple airway infections and day-care attendance were found to be independently associated with asthma and allergic symptoms.