Background Mild cognitive impairment (MCI) and parkinsonism affect many older adults. The objective of this study was to determine the sequence of their occurrence and associated risk of death. Methods 1,255 community-dwelling unimpaired participants from two epidemiological cohorts were examined annually. MCI was based on neuropsychological testing, and parkinsonism was based on the motor portion of the modified Unified Parkinson’s Disease Rating Scale. A multi-state Cox proportional hazards model simultaneously examined incidences of MCI, parkinsonism, and death. Results Average age at baseline was 76.5 years (SD = 7.2) and 73% were female. Incident MCI occurred almost as commonly as incident parkinsonism, yet compared to no impairment, risk of death was higher for MCI (HR = 1.82, 95%CI=1.34, 2.47), but it was not different for parkinsonism (HR = 1.29; 95%CI = 0.95, 1.75). Risk of death for participants with incident MCI who progressed to parkinsonism (40%) was not significantly different from those with MCI alone (HR = 1.25, 95%CI = 0.93, 1.69). However, risk of death for participants with incident parkinsonism who progressed to MCI (51%) was significantly higher than those who did not progress (HR = 1.67, 95%CI = 1.27, 2.18), indicating that risk of death is highest with incidence of MCI. Conclusions The varied patterns of sequential occurrence of cognitive and motor impairment and associated risk of death suggests much greater heterogeneity than previously recognized. Further work is needed to determine the biology underlying the temporal evolution of these phenotypes, and if identification of the various subtypes improves risk stratification.

中文翻译：

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未受损社区老年人轻度认知障碍、帕金森综合征和死亡风险的时间顺序


背景轻度认知障碍 （MCI） 和帕金森病影响许多老年人。本研究的目的是确定其发生顺序和相关死亡风险。方法 每年检查来自两个流行病学队列的 1,255 名社区居民未受损参与者。MCI 基于神经心理学测试，帕金森综合征基于改良的统一帕金森病评定量表的运动部分。多州 Cox 比例风险模型同时检查 MCI 、 帕金森综合征 和 死亡 的发生率。结果 基线时的平均年龄为 76.5 岁 （SD = 7.2），其中 73% 为女性。MCI 事件的发生率几乎与帕金森综合征的发生率一样多，但与无损伤相比，MCI 的死亡风险更高 （HR = 1.82,95%CI=1.34,2.47），但帕金森综合征没有差异 （HR = 1.29;95%CI = 0.95,1.75）。进展为帕金森综合征的 MCI 事件参与者 （40%） 的死亡风险与单独使用 MCI 的参与者没有显著差异 （HR = 1.25,95%CI = 0.93,1.69）。然而，进展为 MCI 的帕金森综合征新发参与者的死亡风险 （51%） 显著高于未进展的参与者 （HR = 1.67， 95%CI = 1.27， 2.18），表明 MCI 发生率的死亡风险最高。结论 认知和运动障碍序列发生的不同模式以及相关的死亡风险表明异质性比以前认识到的要大得多。需要进一步的工作来确定这些表型时间进化的基础生物学，以及各种亚型的鉴定是否能改善风险分层。