Impact of early rapid weight gain on odds for overweight at one year differs between breastfed and formula-fed infants

Abstract

Background: Early rapid weight gain (RWG) increases, whereas longer durations of breastfeeding decreases, odds for later obesity. Objectives: To determine the independent and interactive effects of early weight gain and diet on infant weight status trajectories and odds for overweight at 1 year. Methods: We conducted secondary analysis on data from two longitudinal trials with repeated anthropometric measures. One trial consisted of predominantly or exclusively breastfed (BF, n = 97) infants, whereas the other consisted of exclusively formula-fed (FF, n = 113) infants. Weight-for-length z-score (WLZ) change from 0.5 to 4.5 months was used to categorize early weight gain as slow ( 0.67; RWG). Linear-mixed effects models were fit to examine the independent effects and interaction of early diet (BF, FF) and weight gain (SWG, NWG, RWG) groups on WLZ trajectories; logistic regression was used to assess odds for overweight at 1 year. Results: While similar percentages (41%) of BF and FF infants experienced RWG, we found a significant diet × early weight gain group interaction (P