Department of Environmental and Occupational Health, School of Public Health, Université de Montreal, Montréal, Québec, Canada.
Centre de Recherche du Centre Hospitalier Universitaire de Québec, École de Psychologie, Université Laval, Quebec, Québec, Canada.
Environ Res. 2020 Nov;190:110023. doi: 10.1016/j.envres.2020.110023. Epub 2020 Aug 7.
Organophosphate pesticides are widely used in agriculture and for other purposes, leading to ubiquitous exposure in human populations. Some studies reported cognitive deficits in children exposed prenatally to organophosphate pesticides, but findings from recent studies were inconsistent. Furthermore, recent biomonitoring studies suggest exposure levels have decreased. Hence, the risks from current prenatal exposure to organophosphate pesticides for child neurodevelopment are uncertain. Furthermore, sex-differences also remain to be better documented in relation to potential neurodevelopmental effects.
To examine the association between prenatal exposure to organophosphate pesticides and IQ scores among boys and girls living in several major Canadian cities.
We used data from the MIREC cohort (Maternal-Infant Research on Environmental Chemicals). Women were recruited in 2008-2011 from 10 Canadian cities during their first trimester of pregnancy, and urine spot samples were collected for measurement of three dimethyl alkyl phosphate (DMAP) and three diethyl alkyl phosphate (DEAP) metabolites. When children were 3-4 years of age, we used the Wechsler Preschool and Primary Scales of Intelligence-III (WPPSI-III) to assess cognitive ability of children from 6 out of the 10 cities (Halifax, Hamilton, Kingston, Montreal, Toronto, and Vancouver). We analysed the association between maternal exposure to organophosphate pesticides (DMAP and DEAP urinary metabolites) and children's IQ scores with generalized estimating equations (GEEs) to take into account the clustered-data resulting from the six study sites. All analyses were sex-stratified (n = 296 boys and 311 girls).
The participants were predominantly well-educated, white women, with a relatively high household income. Children had a mean age of 3.4 years at the moment of IQ assessment (range, 3.0-4.1 years). In girls, there was no association between IQ scores and DEAPs or DMAPs. Higher concentrations of DEAPs were significantly associated with poorer Verbal IQ scores (for a 10-fold increase in concentrations, -6.28; 95% CIs, -12.13, -0.43) in boys. The association for Performance IQ in boys also indicated poorer scores with higher DEAP concentrations, but the confidence intervals included the null value (-4.05; 95% CIs, -10.19, 2.10). The relation between DMAPs and IQ scores in boys was also negative, but association estimates were small and not significant.
Urinary metabolites of organophosphate pesticides were not associated with IQ in girls, but we observed that higher maternal urinary DEAPs were associated with poorer Verbal IQ in boys. However, exposure misclassification may be an issue as only one urine sample per woman was analysed. The present study contributes to the accumulating evidence linking exposure to organophosphate pesticides during fetal development with poorer cognitive function in children, bringing data on the risks in a context of low exposure levels encountered in primarily urban populations from Canada.
有机磷农药广泛应用于农业和其他领域，导致人类群体普遍接触。一些研究报告称，产前接触有机磷农药的儿童存在认知缺陷，但最近的研究结果不一致。此外，最近的生物监测研究表明，暴露水平已经下降。因此，目前产前接触有机磷农药对儿童神经发育的风险尚不确定。此外，性别差异与潜在的神经发育影响之间的关系也需要更好地记录。
研究加拿大几个主要城市中产前接触有机磷农药与男孩和女孩智商得分之间的关系。
我们使用了来自母婴环境化学研究（MIREC）队列的数据。2008 年至 2011 年，在女性妊娠的第一个三个月期间，从加拿大 10 个城市招募了这些女性，并采集尿样进行三种二甲基烷基磷酸酯（DMAP）和三种二乙基烷基磷酸酯（DEAP）代谢物的测量。当孩子 3-4 岁时，我们使用韦氏学前和初级智力量表-III（WPPSI-III）来评估来自 6 个城市（哈利法克斯、汉密尔顿、金斯敦、蒙特利尔、多伦多和温哥华）的儿童的认知能力。我们使用广义估计方程（GEE）分析了母体接触有机磷农药（DMAP 和 DEAP 尿代谢物）与儿童智商得分之间的关系，以考虑到来自 6 个研究地点的聚类数据。所有分析均按性别分层（n=296 名男孩和 311 名女孩）。
参与者主要是受过良好教育的白人女性，家庭收入相对较高。在智商评估时，儿童的平均年龄为 3.4 岁（范围为 3.0-4.1 岁）。在女孩中，智商得分与 DEAPs 或 DMAPs 之间没有关联。DEAPs 浓度的升高与男孩的言语智商得分较低显著相关（浓度增加 10 倍，-6.28；95%CI，-12.13，-0.43）。男孩的表现智商的关联也表明，随着 DEAP 浓度的升高，得分较低，但置信区间包括零值（-4.05；95%CI，-10.19，2.10）。DMAPs 与男孩智商得分之间的关系也呈负相关，但关联估计值较小且不显著。
有机磷农药尿代谢物与女孩的智商无关，但我们观察到母体尿中较高的 DEAP 与男孩的言语智商较低有关。然而，由于每个女性仅分析了一个尿液样本，因此可能存在暴露分类错误的问题。本研究有助于积累证据，证明胎儿发育过程中接触有机磷农药与儿童认知功能下降有关，并在加拿大主要城市人群中接触水平较低的情况下提供了相关风险的数据。
