Breastfeeding moderates the association of maternal pre-pregnancy nutritional status with offspring body composition at 30 years.

Maternal pre-pregnancy body mass index is positively associated with offspring obesity, even at adulthood, whereas breastfeeding decreases the risk of obesity. The present study was aimed at assessing whether breastfeeding moderates the association of maternal pre-pregnancy body mass index with offspring body composition at adulthood, using data from 3439 subjects enrolled in a southern Brazilian birth cohort. At 30 years of age, maternal pre-pregnancy body mass index was positively associated with offspring prevalence of obesity, abdominal obesity, as well as body mass index and fat and lean mass index. Breastfeeding moderated the association of maternal pre-pregnancy obesity with offspring adiposity at 30 years of age. For those breastfed<6 months, body mass index was 4.13 kg/m² (95% confidence interval: 2.98; 5.28) higher among offspring of obese mothers, in relation to offspring of normal weight mothers, whereas among those breastfed≥6 months the magnitude of the difference was small [2.95 kg/m² (95% confidence interval: 1.17; 4.73)], p-value for interaction = 0.03. Concerning obesity, among those who had been breastfed < 6 months, the prevalence of obesity was 2.56 (95% confidence interval: 1.98; 3.31) times higher among offspring of obese mothers. On the other hand, among those who were breastfed ≥ 6 months, the prevalence of obesity was 1.82 (95% confidence interval: 1.09; 3.04) times higher among offspring of obese mothers. Therefore, among overweight mothers breastfeeding for more than 6 months should be supported, as it may mitigate the consequences of maternal overweight on offspring body composition.