Environmental Health Department, the National Institute of Public Health, Av. Universidad 655, Col. Santa María Ahucatitlán, CP 62100 Cuernavaca, Morelos, Mexico.
Laboratory of Neurophysiology, the National Institute of Neurology and Neurosurgery, Av. Insurgentes Sur 3877, La Fama, Tlalpan, CP 14269 Mexico City, Mexico.
Sci Total Environ. 2022 Nov 20;848:157519. doi: 10.1016/j.scitotenv.2022.157519. Epub 2022 Jul 21.
Little is known about the neurotoxic effects of chronic exposure to airborne Mn once exposure has been reduced. The environmentally exposed and the reference adult populations evaluated in 2002 were followed, after an environmental management program (EMP) was implemented to reduce the exposure in a mining district in Mexico.
The aim of this study was to compare the association between exposure to Mn and neurocognitive performance in environmentally exposed and reference groups of adults before and after EMP implementation.
In 2013, the same battery of neurocognitive tests used in the initial study (2002) was applied to 58 adults exposed to airborne Mn and 30 adults from the reference community. A cumulative exposure index (CEI) was estimated for the study population before and after the EMP. Categorical outcomes were analyzed using logistic regression, and the resulting ORs were compared between studies. Continuous outcomes were analyzed using linear regression. All models were adjusted for age, years of education, socioeconomic status and blood lead levels.
Exposed adults from the post-EMP study showed an improvement in fine motor and verbal regulation of motor skills (OR < 1) compared to the exposed adults from the pre-EMP study (OR > 1). In both pre- and post-studies, the exposed adults showed a deterioration in their dynamic organization of motor activity compared to the reference group (p < 0.05); however, they showed no significant change in attention and working-memory performance.
After four years of a significant reduction in airborne Mn levels resulting from EMP implementation, chronically exposed adults showed an improvement in fine motor and verbal regulation of motor skills; however, the remaining areas of their motor and cognitive functions remained impaired.
空气中 Mn 的慢性暴露一旦减少，其对神经的毒性影响知之甚少。在墨西哥一个矿区实施环境管理计划（EMP）以降低暴露水平后，对 2002 年评估的环境暴露和参照成人人群进行了随访。
本研究旨在比较暴露于 Mn 与环境暴露和参照组成人在 EMP 实施前后神经认知表现之间的关联。
2013 年，对 58 名接触空气中 Mn 的成年人和 30 名来自参照社区的成年人应用了与初始研究（2002 年）相同的神经认知测试电池。在 EMP 前后为研究人群估计了累积暴露指数（CEI）。使用逻辑回归分析分类结果，并比较研究之间的 OR。使用线性回归分析连续结果。所有模型均调整了年龄、受教育年限、社会经济地位和血铅水平。
与 EMP 前研究中的暴露成年人相比，EMP 后研究中的暴露成年人的精细运动和运动技能的言语调节能力有所改善（OR<1）。在前后两项研究中，暴露成年人的运动活动动态组织能力均较参照组恶化（p<0.05）；然而，他们在注意力和工作记忆表现方面没有明显变化。
在 EMP 实施导致空气中 Mn 水平显著降低四年后，慢性暴露成年人的精细运动和运动技能的言语调节能力有所提高；然而，他们的运动和认知功能的其他方面仍然受损。
