江苏省某县1岁婴儿尿镉与智能发育的关联

Association of urinary cadmium concentration with intellectual development among 1-year-old infants in a county of Jiangsu Province

[背景]镉污染问题日益严峻,越来越多的研究表明镉暴露可能影响儿童的神经系统发育。[目的]评估江苏省某县1岁婴儿尿镉暴露水平,探究其与婴儿智能发育之间的关系。[方法]于2010年选取江苏省某县483名1岁婴儿为研究对象。使用自编问卷收集婴儿的基本信息,婴儿智能发育情况使用0~6岁儿童智能发育筛查测试(DST)评价,以智力指数(MI)及发育商(DQ)定量评价婴儿智能发育情况;同时采集婴儿尿样,应用电感耦合等离子体质谱法测定尿镉浓度。采用多元线性回归模型分析婴儿尿镉浓度与DST得分的关联性,并按尿镉浓度三分位数分组,比较不同水平组MI和DQ得分的差异。[结果]经肌酐校正的婴儿尿镉浓度中位值(P25,P75)为0.235(0.125,0.492)μg·g^(-1)。智力筛查结果显示婴儿MI及DQ的均值±标准差分别为84.19±12.43,86.80±11.82。多元线性回归分析结果显示,婴儿的MI值与尿镉浓度呈负相关(b=-1.55,95%CI:-2.68~-0.42,P=0.007),但DQ值与尿镉浓度的关联无统计学意义(P=0.052),不同尿镉水平儿童的DST得分差异不具有统计学意义(P> 0.05)。性别分层分析结果显示,女婴中尿镉浓度与MI呈负相关(b=-1.84,95%CI:-3.62~-0.05,P=0.043),而男婴中未发现统计学关联(P=0.092)。[结论]镉暴露可能影响婴儿的智力能区发育,且这种影响在女婴中更为显著。

[Background] Cadmium pollution is increasingly serious, and a growing number of studies suggest that cadmium exposure may affect intellectual development of children.[Objective] This study is designed to evaluate urinary cadmium exposure levels of infants aged 1 year living in a county of Jiangsu Province, and explore the association between cadmium exposure and infant intellectual development. [Methods] A total of 483 1-year-old infants were enrolled from a county in Jiangsu Province in 2010. Self-made questionnaires were distributed to obtain basic information of the infants. At the same time, the Developmental Screening Test(DST) for Children Aged 0-6 Years was used to quantitatively evaluate mental index(MI) and development quotient(DQ) as indicators of infant intellectual development. Spot urine samples were collected and cadmium concentrations in urine were measured by inductively coupled plasma mass spectrometery(ICP-MS). A multiple linear regression model was used to analyze the correlation between infants’ urinary cadmium concentrations and DST scores, and the differences of MI and DQ scores were compared among different urinary cadmium exposure groups divided by tertiles. [Results] The median(P25, P75) of creatinine-adjusted urinary cadmium concentration was 0.235(0.125, 0.492) μg·g^(-1). The mean ± standard deviation of MI and DQ scores were 84.19±12.43 and 86.80±11.82, respectively. In the multiple linear regression analysis, MI was negatively correlated with urinary cadmium concentration(b=-1.55, 95% CI:-2.68--0.42, P=0.007), but there was not a significant correlation between DQ and urinary cadmium concentration(P=0.052), and no significant difference in DST scores was observed among different urine cadmium exposure groups(P > 0.05). In the sex-stratified analysis, a negative correlation between urinary cadmium concentration and MI was found in girls(b=-1.84, 95% CI:-3.62--0.05, P=0.043), but not in boys(P=0.092).[Conclusion] Exposure to cadmium may affect the intellectual development of infants, especially of girls.