Original Contribution Breastfeeding, Weight Gain in Infancy, and Overweight at Seven Years of Age The Prevention and Incidence of Asthma and Mite Allergy Birth Cohort Study

Compared with nonbreastfed children, breastfed children tend to have a lower body mass index (BMI) at about 1 year of age. How the BMI of breastfed children develops after the first year when this difference in BMI at 1 year of age is considered is not clear. The authors studied the association between breastfeeding and BMI development from 1 to 7 years of age independently of BMI at 1 year of age. Longitudinal BMI data reported by parents of 2,347 Dutch children born in 1996–1997 who participated in the Prevention and Incidence of Asthma and Mite Allergy birth cohort study were collected. Linear regression and mixed-effects models were used for data analyses. Mean BMI at 1 year of age was 17.2 kg/m2 (standard deviation, 1.4). Compared with nonbreastfed children, children breastfed for>16 weeks had a lower BMI at 1 year of age, after adjustment for confounders (b 0.22, 95% confidence interval:0.39,0.06). The association between breastfeeding and BMI between 1 and 7 years of age was negligible, while a high BMI at 1 year of age was strongly associated with a high BMI between 1 and 7 years of age in the same model. These findings suggest that the lower BMI and lower risk of overweight among breastfed children later in life are already achieved at 1 year of age