Breastfeeding and Protein Intake Influence Body Mass Index from 2 Months to 22 Years in the Cebu Longitudinal Health and Nutrition Survey

Background: Protein intake (PI) may alter adiposity but few studies have explored the age-specific associations of PI with body mass index (BMI). Objective: We analyzed how PI and breastfeeding relate to BMI in the CLHNS (Cebu Longitudinal Health and Nutrition Survey), an observational Filipino birth cohort (1983-2005). Methods: Random-effects longitudinal regression models estimated the association of daily breastfeeding frequency and energy-adjusted PI residuals with concurrent BMI z scores (zBMI) measured bimonthly from 2 to 24 mo (n = 2899), and the association of breastfeeding history and PI residuals with concurrent BMI using 5 surveys from 2 to 22 y (n = 2435). Models included statistical interactions between PI, breastfeeding, age, and energy intake and adjusted for potential confounders. Results: Breastfeeding was associated with higher predicted zBMI at 6 mo (beta: 0.491 SD; 95% CI: 0.422, 0.560) and at 18 mo (beta: 0.114 SD; 95% CI: 0.032, 0.197). Daily breastfeeding frequency contributed to higher predicted zBMI in younger infants and lower predicted zBMI in later infancy. Those with longer breastfeeding history (19 mo) were significantly smaller at age 11 y (in kg/m(2); beta: -0.220; 95% CI: -0.342, -0.097) than those with a shorter (4 mo) breastfeeding duration. Total complementary PI was positively associated with predicted zBMI. Complementary animal PI was positively associated with predicted zBMI in nonbreastfed infants. Plant PI was inversely associated with predicted zBMI of nonbreastfed infants at 6 mo. At 22 y contrasts between high (75th percentile) and low (25th percentile) PIs showed that animal PI was associated with higher predicted BMI (beta: 0.187; 95% CI: 0.045, 0.329), and total PI was inversely related to predicted BMI (beta: -0.008; 95% CI: -0.015, -0.001). Conclusion: Breastfeeding frequency, breastfeeding history, and PI contribute to BMI from infancy to young adulthood in the CLHNS.