Prevalence of allergic diseases and their association with breastfeeding and initiation of complementary feeding in school-age children of Ciudad Guzmán, Mexico.

INTRODUCTION The effect that breastfeeding and complementary feeding practices have on the prevalence of allergic diseases has shown inconsistent results. OBJECTIVE To assess the effect of breastfeeding and the initiation of complementary feeding on the prevalence of allergic disease. POPULATION AND METHODS Analytical, crosssectional population-based study conducted in 6-12 year old children attending primary school and selected through a multistage sampling technique. A structured questionnaire was administered to parents or tutors to identify allergic diseases (asthma, allergic rhinitis, or atopic dermatitis), a history of prolonged breastfeeding and age at initiation of complementary feeding. A logistic regression analysis was used to establish associations among variables. RESULTS A total of 740 children were included. The frequency of breastfeeding for >6 months was 73.4%, and of complementary feeding at <4 months old was 31.9%. Prolonged breastfeeding showed no effect on the prevalence of allergic diseases. A protective effect was observed on the frequency of atopic dermatitis when complementary feeding was initiated late, adjusted OR= 0.36, 95% confidence interval (CI): 0.1-0.8 (p 0.019). CONCLUSIONS The protective effect of breastfeeding against the prevalence of allergic diseases has not been demonstrated. There is a reduction in the prevalence of atopic dermatitis when complementary feeding is started late.