Kim Se-A, Lee Yu-Mi, Lee Ho-Won, Jacobs David R, Lee Duk-Hee
Department of Biomedical Science, Kyungpook National University, Daegu, Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Korea.
Department of Preventive Medicine, School of Medicine, Kyungpook National University, Daegu, Korea.
PLoS One. 2015 Jun 24;10(6):e0130623. doi: 10.1371/journal.pone.0130623. eCollection 2015.
Although cognitive decline is very common in elders, age-related cognitive decline substantially differs among elders and the determinants of the differences in age-related cognitive decline are unclear. We investigated our hypothesis that the association between age and cognition was stronger in those with higher serum concentrations of organochlorine (OC) pesticides, common persistent and strongly lipophilic neurotoxic chemicals. Participants were 644 elders aged 60-85, participating in the National Health and Nutrition Examination Survey 1999-2002. Six OC pesticides (p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodipenyldichloroethylene (DDE), β-hexachlorocyclohexane, trans-nonachlor, oxychlordane, and heptachlor epoxide) were evaluated. "Lower cognitive function" was defined as having a low Digit-Symbol Substitution Test (DSST) score (<25th percentile of DSST score, cutpoint 28 symbols substituted). Higher levels of β-hexachlorocyclohexane, trans-nonachlor, oxychlordane, and heptachlor epoxide modified the associations between age and lower cognitive function (Pinteraction<0.01, 0.03, <0.01, and 0.02, respectively). Elders in the 3rd tertile of these chemicals demonstrated a greater risk of lower cognitive function with aging, compared to those in the combined 1st and 2nd tertiles. Among those with highest OC pesticides (3rd tertile), the odds ratio for the risk of lower cognitive function was about 6 to 11 for the highest quintile of age (80-85 years) vs. the first quintile of age (60-63 years), while the association between age and lower cognitive function became flatter in those with lower OC pesticides (combined 1st and 2nd tertiles). Both DDT and DDE showed no interaction, with lower DSST scores for higher age irrespective of serum concentrations of DDT or DDE. Even though DSST score measures only one aspect of cognition, several OC pesticides modified aging-related prevalence of low cognitive score, a finding which should be evaluated in prospective studies.
尽管认知能力下降在老年人中非常普遍，但与年龄相关的认知能力下降在老年人中存在很大差异，且与年龄相关的认知能力下降差异的决定因素尚不清楚。我们调查了我们的假设，即在血清有机氯（OC）农药浓度较高的人群中，年龄与认知之间的关联更强，OC农药是常见的持久性且具有强亲脂性的神经毒性化学物质。研究对象为644名年龄在60 - 85岁之间、参与1999 - 2002年美国国家健康与营养检查调查的老年人。评估了六种OC农药（p,p'-二氯二苯三氯乙烷（DDT）、p,p'-二氯二苯二氯乙烯（DDE）、β-六氯环己烷、反式九氯、氧氯丹和环氧七氯）。“较低认知功能”被定义为数字符号替换测验（DSST）得分较低（<DSST得分的第25百分位数，切点为替换28个符号）。较高水平的β-六氯环己烷、反式九氯、氧氯丹和环氧七氯改变了年龄与较低认知功能之间的关联（交互作用P值分别<0.01、0.03、<0.01和0.02）。与处于第1和第2三分位数组合的老年人相比，处于这些化学物质第3三分位数的老年人随着年龄增长出现较低认知功能的风险更大。在OC农药含量最高（第3三分位数）的人群中，年龄最大五分位数（80 - 85岁）与年龄最小五分位数（60 - 63岁）相比，出现较低认知功能风险的优势比约为6至11，而在OC农药含量较低（第1和第2三分位数组合）的人群中，年龄与较低认知功能之间的关联则变得较为平缓。DDT和DDE均未显示出交互作用，无论DDT或DDE的血清浓度如何，年龄越大DSST得分越低。尽管DSST得分仅衡量认知的一个方面，但几种OC农药改变了与年龄相关的低认知得分患病率，这一发现应在前瞻性研究中进行评估。
