Werder Emily J, Engel Lawrence S, Curry Matthew D, Sandler Dale P
Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina.
Department of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.
Environ Epidemiol. 2020 Dec 4;4(6):e115. doi: 10.1097/EE9.0000000000000115. eCollection 2020 Dec.
Metals have been shown to have a wide range of neurologic effects across the life course, but most studies consider neurodevelopment or neurodegenerative diseases in older adults. We investigated exposure to metals during adulthood in association with subclinical neurologic endpoints, considering the metals individually and as a mixture, and potential interactions among exposures.
We measured blood levels of cadmium, lead, mercury, manganese, and selenium in 1007 Gulf state residents and estimated cross-sectional associations between ranked levels of blood metals and the presence of self-reported neurologic symptoms. Single pollutant models were mutually adjusted for other metals and we used quantile g-computation to evaluate associations with exposure to the combined mixture. In stratified analyses, we assessed heterogeneity by smoking and blood selenium.
The highest quartile of cadmium was associated with a higher prevalence of central nervous system symptoms (prevalence ratio [PR] = 1.50; 95% confidence interval [CI] = 1.13, 1.99), with stronger associations among nonsmokers (PR = 1.63; 95% CI = 1.11, 2.38) and those with low selenium (PR = 2.29, 95% CI = 1.50, 3.49). Selenium also modified associations between lead and peripheral nervous system symptoms, with increased symptoms in the low selenium group at all quartiles of exposure (-trend = 0.07). Conversely, those with the highest co-exposure to mercury and selenium had reduced neurologic symptoms (PR = 0.73, 95% CI = 0.55, 0.96). Results of the mixture analysis were consistent with single chemical results.
Cadmium exhibited the most consistent relationship with increased neurologic symptoms, though lead was an important exposure in subgroup analyses. Selenium may modify subclinical neurotoxic effects of metals at non-occupational levels in adults.
已有研究表明，金属在整个生命过程中会产生广泛的神经学影响，但大多数研究关注的是老年人的神经发育或神经退行性疾病。我们调查了成年期金属暴露与亚临床神经学终点之间的关联，分别考虑了单一金属以及金属混合物，同时还考虑了暴露之间的潜在相互作用。
我们测量了1007名海湾地区居民血液中的镉、铅、汞、锰和硒水平，并估计了血液金属水平排名与自我报告的神经症状之间的横断面关联。单一污染物模型针对其他金属进行了相互调整，我们使用分位数g计算来评估与混合暴露的关联。在分层分析中，我们按吸烟情况和血液硒水平评估了异质性。
镉的最高四分位数与中枢神经系统症状的较高患病率相关（患病率比[PR]=1.50；95%置信区间[CI]=1.13，1.99），在不吸烟者（PR=1.63；95%CI=1.11，2.38）和低硒者（PR=2.29，95%CI=1.50，3.49）中关联更强。硒还改变了铅与周围神经系统症状之间的关联，在所有暴露四分位数中，低硒组的症状均有所增加（-趋势=0.07）。相反，汞和硒共同暴露最高的人群神经症状减少（PR=0.73，95%CI=0.55，0.96）。混合物分析结果与单一化学物质结果一致。
镉与神经症状增加的关系最为一致，不过在亚组分析中铅也是一种重要的暴露因素。硒可能会改变成年人非职业水平下金属的亚临床神经毒性作用。
