胎儿期低水平汞暴露对婴儿神经行为发育影响的前瞻性研究

Prenatal low level mercury exposure and infant development in the first year:a prospective study in Zhoushan,China

【目的】探讨胎儿期低水平汞暴露对婴儿神经行为发育的影响。【方法】采用整群法选取舟山市定海区第三人民医院产科出生的384名足月新生儿及其母亲,按脐带血汞水平把婴儿分为相对高汞组及相对低汞组,进行3月龄、12月龄发育随访。【结果】高汞组和低汞组发汞值在出生后均显著下降(t=5.58和2.23,P均<0.05)。婴儿发汞和脐带血汞有明显的相关性(r=0.684和0.460,P均<0.01)。分别以3、12月龄发汞为协变量,比较3、12月龄时两组智力发育指数(mental development index,MDI)、神经运动发育指数(psychomotor development index,PDI)的修正均数,差异均无显著性(F值分别为0.376、1.225;0.526、1.010,P均>0.05);协变量对MDI、PDI均数的差异亦无显著性(F值分别为=0.001、0.058;0.430、0.104,P均>0.05)。【结论】尚未发现舟山地区现有胎儿期低水平汞暴露对婴儿神经行为发育有负面影响。

[Objective] To study the association between prenatal mercury exposure and the neurodevelopmentai outcomes of children in Zhoushan Islands at 3 and 12 months of age. [Methods] 384 mother-infant pairs were cluster sampled at Third People＇ Hospital in Zhoushan Islands. Prenatal mercury exposure was determined with Hg analyzer by measuring cord blood mercury （CBHg, Range 1.34-18. 34 ug/L）. Based on their CBHg, children were devided into two exposure groups： 180 in a ＂low＂ mercury group and 204 in a ＂high＂ mercury group. Children were evaluated with the Baylcy Scale of Infant Developnent（BSID） at 3 months of age （n= 358）. The cohort was evaluated again at 12 months （n= 316） with the same method. The association between CBHg concentrations and neurodevelopmental outcomes at 3 and 12 months of age was examined by multiple regression analysis with adjustment for confounding variables. [ Results] The hair mercury of 12-month decreased than that of 3-month significantly. The hair mercury and CBHg were correlated significantly（r=0. 684 and 0. 460, P〈0. 01）. Take 3-month hair mercury levels as covariance, the adjusted mean of MDI and PDI were compared,and there were no statistical significance between two groups（F=0. 376 and 1. 225, P〉0. 05） and there were no statistical significance between covariance and the adjusted means＇ either（F= 0. 001 and 0. 058, P〉0. 05）. Take 12-month hair mercury as covariance, the adjusted mean of MDI and PDI were compared, and there were no statistical significance between two groups（F= 0. 526 and 1. 010 ,P〉0. 05） and no statistical significance between covariance and the adjusted means＇ difference either（F=0. 430 and 0. 104,P〉0.05）. [Conclusion] Our data suggest that prenatal low level mercury exposure have no significant developmental impact on children at both 3 months and 12 months.