Effects of breast feeding on BMI growth trajectories in rural western China: A birth cohort study / 西安交通大学学报(医学版)

ABSTRACT

【Objective】 To describe the BMI growth trajectories from birth to 24 months and examine the effects of fully breastfeeding time and breastfeeding duration on the BMI growth trajectories. 【Methods】 We conducted a follow-up study of a cohort of 1 388 eligible births. Height and weight were measured at birth, every 3 months to 12 months, and every 6 months to 24 months. Detailed demographic, feeding, activity and diseases data were also collected prospectively. Latent growth mixture modeling was conducted to model the BMI growth trajectories from birth to 24 months. Mixed-effects logistic regression analyses were made to examine the impacts of breastfeeding on this outcome. 【Results】 We identified six BMI trajectory patterns in the 1 285 infants analyzed and labeled them as follows "normative growth" (26.6%), "normal-accelerating growth" (8.7%), "normal-decelerating growth" (11.7%), "lower-persistent growth" (6.6%), "rapid growth" (26.8%), and "rapid-accelerating growth" (19.5%). Mixed-effects logistic regression analyses revealed that fully breastfeeding ≥ 3 months could significantly decrease the risk of "rapid growth" (OR=0.71, 95% CI 0.51-0.98) and "rapid-accelerating growth" (OR=0.53, 95% CI 0.37-0.75). After adjustment for confounding factors, the relationship remained significant (OR=0.61, 95% CI 0.41-0.89; OR=0.46, 95% CI 0.31-0.68). Weaning before 6 months could significantly increase the risk of "rapid growth" (OR=1.76, 95% CI 1.19-2.61) and "rapid-accelerating growth" (OR=2.08, 95% CI 1.38-3.14). These associations persisted after adjustment for confounding factors (OR=1.69, 95% CI 1.08-2.71; OR=1.88, 95% CI 1.18-2.99). 【Conclusion】 In rural Western China, the main BMI growth trajectory patterns include "normative growth" , "rapid growth" , and "rapid-accelerating growth" . Prolonging breastfeeding may reduce excess weight gain during infancy.