The Effects of Metals and Gut Microbiota on Weight Gain Patterns in Children Admitted to the Neonatal Intensive Care Unit: A Prospective Cohort Study

Backgrounds: Research indicates that metal exposure and gut microbiota may influence weight gain in children. This study aimed to examine the relationship between metal mixture exposure, gut microbiota composition, and weight gain trajectories among children admitted to the neonatal intensive care unit. Methods: A total of 207 children were recruited from the Children's Hospital of Hunan Province, Central China. Blood metal concentrations were measured using ICP-MS, and gut microbiota composition was determined through 16S rRNA gene sequencing. Group-based trajectory modeling, logistic regression and Bayesian Kernel Machine Regression (BKMR) were used to assess the effects of metal mixtures and gut microbiota on children's weight gain patterns. Results: Four distinct weight gain trajectories were identified over the five-year follow-up: growth retardation group, catch-up growth group, high-end weight group, and normal growth group. Among 26 metals, Cs (OR = 3.208, 95 %CI: 1.107, 9.963), Cu (OR = 3.270, 95 %CI: 1.132, 10.148), W (OR = 3.393, 95 %CI: 1.208, 10.101), As (OR = 0.272, 95 %CI: 0.069, 0.872) and Mn (OR = 0.201, 95 %CI: 0.047, 0.674) were significantly correlated with the growth retardation group. RB41(OR = 9.630, p = 0.016) and Bacteroides (OR=0.272, p = 0.011) in gut microbiota were correlated with the growth retardation group. Conclusion: Mn, As, Cs, Cu, W, Zn and Sb in 26 metals, RB41 and Bacteroides in gut microbiota were associated with the trajectory patterns of children. Maintaining optimal blood metal levels and regulating gut microbiota composition during early infancy may have important implications for promoting healthy weight gain trajectories in early childhood.