Abstract MP62: Associations of Timing of Complementary Feeding Introduction and Adiposity Throughout Childhood and Adolescence

Abstract

Introduction: Complementary feeding includes introducing food or beverages other than breastmilk or formula to infants. We previously showed associations of early complementary feeding (<4 months old) with higher obesity risk at 3 years old in formula-fed children only. Hypothesis: We hypothesized that associations with adiposity would persist into early adolescence. Methods: Among 991 children from Project Viva, a pre-birth prospective cohort, we examined associations of complementary feeding timing with later body mass index (BMI) z-scores, waist circumference, and dual-energy radiograph absorptiometry (DXA) measured adiposity in mid-childhood (mean: 7.8, SD 0.8 years old; N=681) and in early adolescence (mean: 13.2, SD 0.9 years old; N=637). We used linear regression models adjusted for socio-demographic characteristics, parental BMI, and change in weight-for-age z-score from 0 to 4 months (as a marker of early infant growth); the reference group for all analyses was complementary feeding initiation between 4 to <6 months. We ran separate models for infants who were breastfed for ≥4 months (breastfed) and infants who were never breastfed or weaned <4 months of age (formula-fed). As a secondary analysis, we fitted individual BMI trajectories using mixed-effect models with natural cubic spline functions (N=952), and then examined the association of timing of complementary feeding with age at BMI rebound derived from the trajectories, using linear regression models, adjusting for previously listed covariates. Results: At 4 months of life, 66% (654 of 991) of children were breastfed and 34% (337 of 991) were formula-fed. Complementary feeding was introduced <4 months for 19% (188 of 991), between 4 to <6 months for 68% (674 of 991; reference group), and ≥6 months for 13% (129 of 991) of children. Complementary feeding <4 months was associated with higher waist circumference in both formula-fed (β 2.60, 95% CI [0.35, 4.86] cm) and breastfed children (1.98 [0.07, 3.89] cm) in mid-childhood, while in early adolescence, it was associated with higher BMI z-score (0.36 [0.04, 0.68]) in formula-fed children, and with higher waist circumference in both formula-fed (4.99 [1.14, 8.84] cm) and breastfed children (3.12 [0.02, 6.21] cm). Complementary feeding <4 months was additionally associated with an earlier age at BMI rebound (-7.6 [-12.6, -2.5] months) in breastfed children. Complementary feeding initiated ≥6 months was associated with higher BMI z-score (0.50 [0.04, 0.97]) in mid-childhood and with an earlier age at BMI rebound (-11.5 [-20.0, -2.9] months) in formula-fed children only. Conclusions: We found associations of both early and late introduction of complementary feeding with BMI z-score in formula-fed infants and with waist circumference in breastfed and formula-fed infants throughout childhood.