Timing of Complementary Feeding Introduction and Adiposity Throughout Childhood

This study examines associations of timing of CF introduction with adiposity throughout childhood and adolescence in the US Project Viva prospective cohort study. OBJECTIVES: To examine associations of the timing of complementary feeding (CF) introduction with adiposity throughout childhood. METHODS: We studied 1013 children from Project Viva. Our exposure was CF introduction, categorized as <4 months (19%), 4 to <6 months (68%; reference group), and >= 6 months of age (14%). Our outcomes included adiposity measures in midchildhood (mean: 7.9 years; SD 0.8; n = 896) and early adolescence (mean: 13.2 years; SD 0.9; n = 850). We used linear regression models adjusted for potential confounders and ran separate models for infants who were breastfed at least partly for >= 4 months (categorized as breastfed; 69%) and infants who were never breastfed or stopped breastfeeding at <4 months (categorized as formula fed; 31%). RESULTS: CF initiated at <4 months was associated with higher adiposity in midchildhood in breastfed children; associations persisted into adolescence for waist circumference, truncal fat mass, and the sum of subscapular and triceps skinfolds (eg, waist circumference: confounder-adjusted beta 2.97 [95% confidence interval (CI) 0.47 to 5.47] cm). The effect estimates were larger in formula-fed children, with more associations persisting into adolescence (eg, waist circumference: adjusted beta 3.42 [95% CI 0.12 to 6.71] cm). CF initiated at >= 6 months was associated with a higher subscapular/triceps skinfold ratio in midchildhood and adolescence (adjusted beta 0.13 [95% CI 0.02 to 0.25]) in formula-fed children. CONCLUSIONS: We found associations of early CF introduction with higher adiposity measurements in breastfed and formula-fed children and associations of late introduction of CF with higher adiposity in formula-fed children.