Association between placental single and mixed metals and offspring weight trajectories: a prospective birth cohort study.

There is insufficient knowledge about the cumulative metal exposure during the fetal period and the physical development trajectories of offspring, and the placenta is a suitable biological matrix for evaluating cumulative metal exposure. This study utilized data from the Ma'anshan Birth Cohort (MABC), which includes 16 repeated weight measurements from 0 to 6 years. Placental tissue samples were analyzed for 17 metals. Graph-Based Trajectory Model (GBTM) was used to analyze and fit weight trajectories. The results found single-metal exposure analyses demonstrated that non-essential metals arsenic (As) and cesium (Cs) exhibited significant positive associations with Low-Rising weight-for-age Z-scores (WAZ) trajectories both in 0 to 2 years [ As, [odds ratio (OR): 1.33, 95 % CI: 1.06-1.68], (Cs, OR: 1.14, 95 % CI: 0.99-1.32)] years and 0 to 6 years [As, (OR: 1.46, 95 % CI: 1.15-1.85), (Cs, OR: 1.16, 95 % CI: 1.00-1.35)]. The essential metal Co was positively correlated with High-Rising WAZ trajectories aged from 0 to 2 years (OR: 1.31, 95 % CI: 1.03-1.65) and High-Stable WAZ trajectories aged from 0 to 6 years (OR: 1.25, 95 % CI: 1.02-1.53). Essential metals molybdenum (Mo) (OR: 1.37, 95 % CI: 1.00-1.87) and copper (Cu) (OR: 1.39, 95 % CI: 1.04-1.85) were significantly linked to Low-Rising trajectories specifically aged from 0 to 6 years, while Fe was was positively correlated with Low-Stable trajectories aged from 0 to 6 years (OR: 0.80, 95 % CI: 0.64-1.01). Our study found a positive correlation between placental metal mixtures and the low-rising weight-for-age Z-score (WAZ) trajectory. Among these metals, non-essential metals showed a more significant association with the outcome, with As contributing the most prominently. In summary, we found that As, Cs, Cu, Mo, and iron (Fe) in the placenta are key metals influencing children's weight development trajectories, with high levels of As and Cs leading to the development of a persistent Low-Rising trajectory in early life.