Pesticides are widely-used chemicals commonly applied in agriculture for the protection of crops from pests. Depending on the class of pesticides, the specific substances may have a specific set of adverse effects on humans, especially in cases of acute poisoning. In past years, evidence regarding sequelae of chronic, low-level exposure has been accumulating. Cognitive impairment and dementia heavily affect a person's quality of life and scientific data has been hinting towards an association between them and antecedent chronic pesticide exposure. Here, we reviewed animal and human studies exploring the association between pesticide exposure, cognition and dementia. Additionally, we present potential mechanisms through which pesticides may act neurotoxically and lead to neurodegeneration. Study designs rarely presented homogeneity and the estimation of the exposure to pesticides has been most frequently performed without measuring the synergic effects and the possible interactions between the toxicants within mixtures, and also overlooking low exposures to environmental toxicants. It is possible that a Real-Life Risk Simulation approach would represent a robust alternative for future studies, so that the safe exposure limits and the net risk that pesticides confer to impaired cognitive function can be examined. Previous studies that evaluated the effect of low dose chronic exposure to mixtures of pesticides and other chemicals intending to simulate real life exposure scenarios showed that hermetic neurobehavioral effects can appear after mixture exposure at doses considered safe for individual compounds and these effects can be exacerbated by a coexistence with specific conditions such as vitamin deficiency. However, there is an overall indication, derived from both epidemiologic and laboratory evidence, supporting an association between exposure to neurotoxic pesticides and cognitive dysfunction, dementia and Alzheimer's disease.

中文翻译：

---

农药、认知功能和痴呆症：综述

农药是广泛使用的化学品，通常在农业中使用，以保护作物免受害虫侵害。根据农药的类别，特定物质可能对人类产生一系列特定的不利影响，尤其是在急性中毒的情况下。在过去的几年里，关于慢性低水平暴露后遗症的证据一直在积累。认知障碍和痴呆症严重影响一个人的生活质量，科学数据已经暗示它们与之前的慢性农药暴露之间存在关联。在这里，我们回顾了探索农药暴露、认知和痴呆之间关联的动物和人类研究。此外，我们还介绍了农药可能产生神经毒性并导致神经变性的潜在机制。研究设计很少呈现同质性，并且最常进行农药暴露的估计，而没有测量协同效应和混合物中有毒物质之间可能的相互作用，也忽略了对环境毒物的低暴露。现实生活中的风险模拟方法可能代表未来研究的可靠替代方案，以便可以检查安全暴露限值和农药对认知功能受损的净风险。先前的研究评估了低剂量长期暴露于杀虫剂和其他化学物质混合物的影响，旨在模拟现实生活中的暴露场景，结果表明，在以对单个化合物安全的剂量暴露混合物后，可能会出现密封的神经行为效应，并且这些效应可能会因以下原因而加剧：与特定条件共存，例如维生素缺乏症。然而，从流行病学和实验室证据得出的总体迹象表明，暴露于神经毒性农药与认知功能障碍、痴呆和阿尔茨海默病之间存在关联。