Protective effect of breastfeeding against overweight can be detected as early as the second year of life: a study of children from one of the most socially-deprived areas of Brazil.

Millions of children live in Brazil's semi-arid region, one of the most socially-deprived areas of the country, where undernutrition co-exists with obesity as a consequence of the nutrition transition. There is evidence that childhood obesity predisposes adult obesity and, thus, that obesity should be prevented as early as possible. Some studies have shown that breastfeeding is a protective factor against overweight and obesity while other studies have not found this association. There have been few studies on this association in developing countries and of children below two years of age. The present study aimed to investigate whether children exposed to exclusive breastfeeding for ≥ 6 months showed a lower prevalence of overweight in the second year of life, based on a probability sample of 2,209 children (aged 12 to 24 months). The dependent variable was overweight, defined as weight-for-length z-scores of >2, based on the WHO 2006 standard while the independent variable was exclusive breastfeeding (≥ 6 months). The prevalence ratio (PR) and its 95% CI were estimated using Poisson regression with robust adjustment of variance. After adjusting for potential confounding factors (socioeconomic, demographic and health-related variables), children on exclusive breastfeeding for ≥ 6 months showed a lower prevalence of overweight (5.7% vs 9.1%, PR 0.62, 95% CI 0.45-0.89). It was found that exclusive breastfeeding for six months or more is a protective factor against overweight in children in the second year of life living in the Brazilian semi-arid region.