[A cohort study of association between sleep duration and cognitive impairment in the elderly aged 65 years and older in China].

Objective: To explore the effect of sleep duration on the risk of cognitive impairment in the elderly in China. Methods: Baseline data of 9 679 elderly individuals with intact cognition were collected from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2005, and followed up was conducted until 2018. Cox proportional hazards model was used to analyze the association between different sleep durations and the risk for cognitive impairment in the elderly. Results: Compared with elderly with sleep duration of 6 hours per day, those with sleep duration less than 5 hours had increased risk for cognitive impairment by 30% (HR=1.30, 95%CI: 1.05-1.62), and those with sleep durations of 7 hours, 8 hours and more than 9 hours had increased risk for cognitive impairment by 34% (HR=1.34,95%CI: 1.09-1.64), 40% (HR=1.40,95%CI: 1.17-1.69) and 43% (HR=1.43,95%CI: 1.19-1.70), respectively. Trend test showed that the risk of cognitive impairment increased with the extension of sleep duration (>6 h), and there was a dose-response relationship (P<0.001). However, self-rated sleep quality was not associated with the risk for cognitive impairment in the elderly. Conclusions: The shorter and longer sleep duration were associated an increased risk of cognitive impairment in the elderly aged ≥65 years in China, suggesting that optimizing sleep duration might delay the occurrence of cognitive impairment.目的： 探讨我国老年人睡眠时长对认知障碍发生风险的影响。 方法： 将2005年中国老年健康影响因素跟踪调查招募的9 679名认知完好老年人的调查信息作为基线数据，随访该队列人群至2018年，采用Cox比例风险回归模型分析老年人的不同睡眠时长与其认知障碍发生风险的关联。 结果： 与睡眠时长为6 h的老年人比较，睡眠时长≤5 h的老年人发生认知障碍风险增加30%（HR=1.30，95%CI：1.05~1.62），睡眠时长为7、8和≥9 h的老年人发生认知障碍风险分别增加34%（HR=1.34，95%CI：1.09~1.64）、40%（HR=1.40，95%CI：1.17~1.69）和43%（HR=1.43，95%CI：1.19~1.70）。趋势检验显示，随着睡眠时间的延长（>6 h）老年人发生认知障碍的风险增加，存在剂量反应关系（P<0.001）。而自评睡眠质量与老年人认知障碍的发生风险无关。 结论： 我国≥65岁老年人的睡眠时间过短和过长可以增加其患认知障碍的发生风险，优化睡眠时长可以延缓认知障碍的发生。.