Department of Psychology, Université du Québec à Montréal, Québec, Canada; Sainte-Justine University Hospital Research Center, Montréal, Québec, Canada.
Department of Psychology, Université du Québec à Montréal, Québec, Canada; Sainte-Justine University Hospital Research Center, Montréal, Québec, Canada; Centre for Interdisciplinary Studies in Biology, Health, Society and Environment (CINBIOSE), Université du Québec à Montréal, Québec, Canada.
Neurotoxicology. 2018 Jan;64:118-125. doi: 10.1016/j.neuro.2017.08.015. Epub 2017 Sep 18.
Manganese is commonly found in water but potential neurotoxic effects from exposure through drinking water are poorly understood. We previously reported a cross-sectional study showing that drinking water Mn concentration was associated with lower IQ in children aged 6 to 13 years.
For this follow-up study, we aimed to re-assess the relation between exposure to Mn from drinking water and IQ at adolescence. In addition, we aimed to examine whether changes in drinking water Mn concentration was associated with changes in IQ scores.
From the 380 children enrolled in the baseline study, 287 participated to this follow-up study conducted in average 4.4 years after. Mn concentration was measured in home tap water and children's hair. The relationships between these Mn exposure indicators and IQ scores (Weschsler Abbreviated Scale of Intelligence) at follow-up were assessed with linear regression analysis, adjusting for potential confounders. Intra-individual differences in IQ scores between the two examinations were compared for children whose Mn concentration in water remained stable between examinations, increased or decreased.
The mean age at follow-up was 13.7 years (range, 10.5 to 18.0 years). Geometric mean of Mn concentration in water at follow-up was 14.5μg/L. Higher Mn concentration in water measured at follow-up was associated with lower Performance IQ in girls (β for a 10-fold increase=-2.8, 95% confidence intervals [CI] -4.8 to -0.8) and higher Performance IQ in boys (β=3.9, 95% CI 1.4 to 6.4). IQ scores were not significantly associated with Mn concentration in hair, although similar trends as for concentration in water were observed. For children whose Mn concentration in water increased between baseline and follow-up, Performance IQ scores decreased significantly (intra-individual difference, -2.4 points).
Higher levels of Mn in drinking water were associated with lower Performance IQ in girls, whereas the opposite was observed in boys. These findings suggest long-term exposure to Mn through drinking water is associated differently with cognition in boys and girls.
锰广泛存在于水中，但人们对通过饮用水暴露于其中可能产生的神经毒性作用知之甚少。我们之前的一项横断面研究报告显示，6 至 13 岁儿童的饮用水锰浓度与智商降低有关。
在这项随访研究中，我们旨在重新评估饮用水中锰暴露与青少年时期智商之间的关系。此外，我们旨在研究饮用水中锰浓度的变化是否与智商评分的变化有关。
在基线研究中招募的 380 名儿童中，有 287 名儿童参加了本次随访研究，平均随访时间为 4.4 年。在家用自来水和儿童头发中测量了锰浓度。在校正了潜在混杂因素后，采用线性回归分析评估了这些锰暴露指标与随访时智商评分（Weschsler 简明智力量表）之间的关系。比较了两次检查之间水锰浓度保持稳定、增加或减少的儿童之间的智商评分个体内差异。
随访时的平均年龄为 13.7 岁（范围，10.5 至 18.0 岁）。随访时水中锰的几何均数为 14.5μg/L。随访时水中锰浓度较高与女孩的操作智商较低相关（每增加 10 倍的β值为-2.8，95%置信区间[CI]为-4.8 至-0.8），而与男孩的操作智商较高相关（β值为 3.9，95%CI 为 1.4 至 6.4）。虽然观察到与水中浓度相似的趋势，但头发中锰浓度与智商评分无显著相关性。与基线和随访期间水中锰浓度增加的儿童相比，操作智商评分显著降低（个体内差异为-2.4 分）。
饮用水中锰含量较高与女孩的操作智商较低有关，而男孩则相反。这些发现表明，长期通过饮用水暴露于锰会对男孩和女孩的认知产生不同的影响。
