Association of Breastfeeding Duration with Body Composition in Children Aged 3-5 Years

This study aimed to assess the relationship between the body composition of children aged 3-5 years and breastfeeding status and duration. The study was conducted using data from the National Nutrition and Health Systematic Survey for children 0-17 years of age in China (CNHSC), a nationwide cross-sectional study. Breastfeeding information and potential confounders were collected using standardized questionnaires administered through face-to-face interviews. The body composition of preschool children was measured using bioelectrical impedance analysis. A multivariate linear regression model was used to assess the relationship between breastfeeding duration and body composition after adjusting for potential confounders. In total, 2,008 participants were included in the study. Of these, 89.2% were ever breastfed and the median duration of breastfeeding was 12 months (IQR 7-15 months). Among children aged 3 years, the height-for-age -score (HAZ) for the ever breastfed group was lower than that for never breastfed group (0.12 . 0.42, = 0.043). In addition, the weight-for-age -score (WAZ) of the ever breastfed group was lower than that of the never breastfed group (0.31 . 0.65, = 0.026), and the WAZ was lower in children aged 4 years who breastfed between 12 and 23 months than in those who never breastfed. Compared to the formula-fed children, the fat-free mass of breastfed infants was higher for children aged 3 years (12.84 kg . 12.52 kg, = 0.015) and lower for those aged 4 years (14.31 kg . 14.64 kg, = 0.048), but no difference was detected for children aged 5 years (16.40 kg . 16.42 kg, = 0.910) after adjusting for potential confounders. No significant difference was detected in the weight-for-height -score (WHZ), body mass index (BMI)-for-age -score (BAZ), fat-free mass index, and body fat indicators in the ever breastfed and never breastfed groups and among various breastfeeding duration groups for children aged 3-5 years. No obvious associations were detected between breastfeeding duration, BMI, and fat mass indicators. Future prospective studies should explore the relationship between breastfeeding status and fat-free mass.