孕期环境重金属暴露与儿童体格发育水平及生长轨迹关联的研究进展

Research progress on environmental heavy metal exposure during pregnancy and children's physical development level and growth trajectory

孕期环境重金属低水平暴露问题普遍,该阶段暴露易对胎儿生长发育产生不良的影响,并可持续至出生后。本文系统回顾了近年来国内外有关孕期重金属暴露与儿童体格发育的流行病学研究,重点讨论了镉、汞、铅、砷4种常见重金属与儿童体格发育水平及生长轨迹的关联。现有研究结果显示,孕期镉、汞暴露与儿童早期肥胖有关,孕期铅暴露可致儿童肥胖与生长迟缓的双重效应,孕期砷暴露则与儿童生长迟缓相关。同时,孕期镉、铅暴露对男童的影响更显著,存在性别效应。儿童生长轨迹分析的多数研究结果则显示,孕期镉、砷和铅暴露常与较低的儿童体质指数(BMI)/年龄别体重Z分数(WAZ)和年龄别身高Z分数(HAZ)生长轨迹存在关联,甚至可持续至青春期,其中孕早期和孕晚期可能分别是镉和铅暴露作用效应的关键窗口期。由于汞暴露评价方法的不同,孕期汞暴露对儿童生长轨迹影响的结果尚存争议。此外,孕期重金属混合暴露对儿童体格生长发育的作用可能存在联合效应。未来仍需要结合多种样本来源、多时点的人群流行病学研究,进一步阐明单一金属和多种重金属间交互对儿童体格发育的影响,并加强基础性研究以拓宽其中关联机制的新认识。

Low-level exposure to environmental heavy metals during pregnancy is common,and the effects of such exposure on the growth and development of the fetus may continue after birth.In this paper,we reviewed the epidemiological studies on heavy metal exposure during pregnancy and children's physical development at home and abroad in recent years,focusing on the associ-ations between four common heavy metals,namely,cadmium,mercury,lead,and arsenic,and children's physical development levels and growth trajectories.The results of existing studies showed that cadmium and mercury exposure during pregnancy was associated with early child-hood obesity,lead exposure during pregnancy may lead to dual effects of childhood obesity and growth retardation,and arsenic exposure during pregnancy was associated with childhood growth retardation.At the same time,cadmium and lead exposure during pregnancy had a more significant effect on boys,and there was a sex effect.Most studies of children's growth trajectory showed that exposure to cadmium,arsenic,and lead during pregnancy was often associated with lower childhood body mass index(BMI)/weight-for-age Z-score(WAZ)and height-for-age Z-score(HAZ)growth trajectories,even into adolescence,where the first trimester and the third trimester may be critical windows for cadmium and lead exposure,respectively.The results of mercury exposure during pregnancy associated with children's growth trajectories were contro-versial due to differences in methods for evaluating mercury exposure.In addition,there may be certain combined effects of mixed exposure to heavy metals during pregnancy on the physical growth and development of children.There is still a need to further elucidate the effects of single metal and multiple heavy metal interactions on children's physical development by combining population-based epidemiological studies with multiple sample sources and time points,and to strengthen basic research to broaden the new understanding of involved mechanisms.