Breastfeeding, complementary feeding, overweight and obesity in pre-school children.

OBJECTIVE To analyze the association of overweight and obesity with breastfeeding and complementary feeding in pre-school children. METHODS Cross-sectional study with 566 children, enrolled in private schools of the city of São Paulo, Southeastern Brazil, in 2004-2005. The dependent variable was overweight and obesity. Body Mass Index percentile curves were employed to classify children's nutritional status, considering values > or =P85 and or =P95 as obesity. The following explanatory variables were analyzed: child and family socio-demographic characteristics; birth weight; parents' nutritional status; breastfeeding; complementary feeding; and current feeding. Analysis of association between explanatory variables and outcome was performed with simple logistic regression and multiple logistic regression with hierarchical model. RESULTS Prevalence of overweight and obesity in the population studied was 34.4%. The following were protective factors against overweight and obesity: exclusive breastfeeding for six months or more (95% CI [0.38;0.86]; OR=0.57; p=0.02) and breastfeeding for more than 24 months (95% CI [0.05;0.37]; OR=0.13; p=0.00). CONCLUSIONS Results suggest that breastfeeding can protect children against overweight and obesity, thus representing yet another advantage of maternal milk.