Infections in Child Day Care Centers and Later Development of Asthma, Allergic Rhinitis, and Atopic Dermatitis

OBJECTIVE: To evaluate the effect of successful prevention of common infections in child day care centers on the later development of allergic diseases. DESIGN: Prospective follow-up survey with a questionnaire administered 12 years after a controlled randomized hygiene intervention. SETTING: Twenty municipal child day care centers in Oulu, Finland. PARTICIPANTS: A questionnaire was sent to 1354 prior participants (98%) in the intervention trial. The response rate was 68% (928 of 1354 participants). MAIN INTERVENTION: Hygiene intervention from March 1, 1991, to May 31, 1992. MAIN OUTCOME MEASURES: The number of respondents who had a diagnosis of asthma, allergic rhinitis, and/or atopic dermatitis made by a physician, and the number of those who reported symptoms of atopic diseases. RESULTS: Asthma was diagnosed by a physician in 48 of the 481 respondents (10%) from the intervention child day care centers, with markedly fewer infections, and in 46 of the 447 controls (10%) (relative risk, 1.0; 95% confidence interval, 0.7-1.4). Similarly, no differences were found in the numbers of children who had a diagnosis of other atopic diseases or who had reported such symptoms. CONCLUSION: The prevention of common respiratory tract and enteric infections during early childhood does not change later allergic morbidity.