Objective: To investigate the latent effect of breastfeeding on overweight and obesity in late childhood.
Methods: Data on breastfeeding and child anthropometric measurements were collected annually from a nation-wide population-based prospective cohort study in Japan (21,425 boys and 20,147 girls). Breastfeeding status (exclusiveness and duration) was assessed when the child was 6 months old. Mixed effects models were used to evaluate trajectories of body mass index (BMI), together with overweight and obesity status, from 1.5 to 8 years of age.
Results: Mixed-fed boys and exclusively breastfed boys showed lower BMI as the main effect, as well as a slower increase of inclination in BMI as interaction term between feeding type and age, than exclusively formula-fed boys. Breastfed boys had lower BMI at the ages of 7 and 8, in comparison with exclusively formula fed boys (P = 0.002 and P < 0.001, respectively). A similar association was found for girls, although the main effect of feeding type was not statistically significant. The analysis of breastfeeding duration had similar results.
Conclusions: Breastfeeding, even if partial or for short duration, has a latent protective effect against overweight and obesity in late childhood, especially for boys.
Keywords: bottle feeding; breastfeeding; epidemiology; obesity; overweight.
Copyright © 2014 The Obesity Society.