Kröger Edeltraut, Verreault René, Carmichael Pierre-Hugues, Lindsay Joan, Julien Pierre, Dewailly Eric, Ayotte Pierre, Laurin Danielle
Centre d'Excellence sur le Vieillissement de Quebec, Unite de Recherche sur le Vieillissement, Centre de Recherche FRSQ du Centre Hospitalier Affilie Universitaire de Québec, Québec, Canada.
Am J Clin Nutr. 2009 Jul;90(1):184-92. doi: 10.3945/ajcn.2008.26987. Epub 2009 May 27.
Omega-3 polyunsaturated fatty acids (n-3 PUFAs) may protect against dementia, although epidemiologic studies have yielded inconclusive results. Fish is the main dietary source of n-3 PUFAs and is sometimes contaminated with mercury. This neurotoxicant may modify the association with dementia.
We evaluated the association of erythrocyte membrane total n-3 PUFAs, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and blood mercury with the incidence of dementia and Alzheimer disease (AD) in the Canadian Study of Health and Aging (CSHA) with adjustment for confounders including apolipoprotein E epsilon4 (APOE epsilon4) status.
The CSHA is a cohort study of a representative sample of persons aged > or =65 y, conducted from 1991 to 2002. A subsample of 663 nondemented CSHA subjects with a complete clinical examination, blood samples, and follow-up information was eligible for prospective analyses on laboratory measurements. Of these, 149 were incident cases of dementia, including 105 with AD.
In adjusted Cox regression models with age as the time scale, there were no associations between total n-3 PUFAs, DHA, or EPA and dementia or AD. In contrast, a mercury concentration in the highest quartile was associated with a reduced risk of dementia (hazard ratio: 0.53; 95% CI: 0.33, 0.88). However, significant risk reductions were limited to subjects with concentrations of both n-3 PUFAs and mercury that were above the median. There was no modification of risk by APOE epsilon4 status.
No associations between n-3 PUFAs and dementia or AD were found. The results regarding mercury may indicate a spurious association.
ω-3多不饱和脂肪酸（n-3 PUFAs）可能对痴呆症具有预防作用，尽管流行病学研究结果尚无定论。鱼类是n-3 PUFAs的主要饮食来源，且有时会被汞污染。这种神经毒素可能会改变与痴呆症的关联。
在加拿大健康与老龄化研究（CSHA）中，我们评估了红细胞膜总n-3 PUFAs、二十二碳六烯酸（DHA）、二十碳五烯酸（EPA）以及血汞与痴呆症和阿尔茨海默病（AD）发病率之间的关联，并对包括载脂蛋白Eε4（APOEε4）状态在内的混杂因素进行了校正。
CSHA是一项针对年龄≥65岁人群的代表性样本的队列研究，于1991年至2002年进行。663名未患痴呆症的CSHA受试者的子样本，这些受试者进行了完整的临床检查、血液样本采集及随访信息，符合对实验室测量进行前瞻性分析的条件。其中，149例为痴呆症新发病例，包括105例AD患者。
在以年龄为时间尺度的校正Cox回归模型中，总n-3 PUFAs、DHA或EPA与痴呆症或AD之间均无关联。相比之下，汞浓度处于最高四分位数与痴呆症风险降低相关（风险比：0.53；95%置信区间：0.33，0.88）。然而，显著的风险降低仅限于n-3 PUFAs和汞浓度均高于中位数的受试者。APOEε4状态未对风险产生影响。
未发现n-3 PUFAs与痴呆症或AD之间存在关联。关于汞的结果可能表明存在虚假关联。
