Little attention has been paid to neurotoxicants on the risk of dementia. Exposure to known neurotoxicants such as polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides is suspected to have adverse cognitive effects in older populations. To assess whether plasma concentrations of PCBs and OC pesticides are associated with the risk of cognitive decline, Alzheimer’s disease (AD) and of all-cause dementia in the Canadian older population. Analyses were based on data from the Canadian Study of Health and Aging, a 3-phase, 10-year population-based study of individuals aged 65+ years. Analyses included 669 clinically assessed subjects, of which 156 developed dementia including 108 incident cases of AD. Subjects were screened at each phase with the 100-point Modified Mini-Mental State Examination (3MS), a measurement of global cognitive function. Statistical analyses included Cox proportional hazards model when the outcome was dementia or AD, and a repeated-measure mixed model when the outcome was the 3MS score. No association of PCB and OC pesticides with the risk of dementia and AD was observed. Elevated concentrations of PCB congeners nos 118, 153, 156, 163, and OC pesticides 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p’-DDT) and its metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p’-DDE) were significantly associated with cognitive decline as assessed with the 3MS. A posteriori analyses suggested that only p,p’-DDE was significantly related to a higher cognitive decline in time based on the 3MS among incident cases of dementia compared to subjects remaining nondemented. PCB and OC pesticide plasma concentrations were not related to the incident diagnosis of neither dementia, nor AD. Using the 3MS scores as the outcome, higher concentrations of four PCB congeners and two OC pesticides were associated with lower cognitive performances in subjects. The association of p,p’-DDE with cognitive decline in time in incident cases of dementia merits further investigation.

中文翻译：

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老年人中多氯联苯和有机氯农药的暴露以及痴呆，阿尔茨海默氏病和认知能力下降的风险：来自加拿大健康与老龄化研究的前瞻性分析

关于痴呆症风险的神经毒性研究很少。怀疑暴露于已知的神经毒剂，例如多氯联苯（PCBs）和有机氯（OC）农药对老年人群有不利的认知作用。为了评估PCB和OC农药的血浆浓度是否与加拿大老年人口的认知下降，阿尔茨海默氏病（AD）和全因痴呆症的风险相关。分析基于加拿大健康与老龄化研究的数据，该研究是一项为期10年，为期3年的针对65岁以上人群的基于人口的研究。分析包括669名经过临床评估的受试者，其中156名发展为痴呆症，包括108例AD事件。在每个阶段都对受试者进行了100点修改的迷你精神状态检查（3MS），整体认知功能的度量。统计分析包括当结局为痴呆或AD时的Cox比例风险模型，以及当结局为3MS评分时的重复测量混合模型。没有观察到PCB和OC农药与痴呆和AD的风险相关。118、153、156、163和OC农药1,1,1-三氯-2,2-双（对氯苯基）乙烷（p，p'-DDT）及其代谢产物1,1的PCB同类化合物的浓度升高用3MS评估，-dichloro-2,2-bis（p-氯苯基）乙烯（p，p'-DDE）与认知能力下降显着相关。后验分析表明，与3d保持非痴呆的受试者相比，痴呆事件中只有p，p'-DDE与3MS的认知时间下降显着相关。PCB和OC农药的血浆浓度与痴呆症或AD的事件诊断均无关。使用3MS评分作为结果，受试者中4种PCB同系物和2种OC农药的较高浓度与较低的认知能力有关。在痴呆事件中，p，p'-DDE与认知时间下降的关联值得进一步研究。