Zhongguo quanke yixue (Apr 2023)
Association of Nighttime Sleep Duration with Cognitive Impairment among Community-dwelling Older Adults
Abstract
Background With the rapid population aging in China, cognitive impairment in older adults has become a growing public health concern. Objective To examine the association between nighttime sleep duration and cognitive impairment among community-dwelling older adults. Methods Data were derived from the cohort of Older Adult Health and Modifiable Environmental Factors established in Fuyang City from July to September 2018, among whom a total of 4 837 older adults with complete data on cognitive function and sleep time were included in this study. General demographic characteristics〔gender, age, living area (urban or rural), education level, occupation, marital status〕, living habits, the history of chronic diseases, sleep duration, and overall cognitive function were extracted. Binary Logistic regression models were used to analyze the association between nighttime sleep duration and cognitive impairment. Restrictive cubic splines were used to further determine potential dose-response relationships between them. Results The participants had a mean nighttime sleep duration of (6.95±1.75) hours, among whom 1 773 (36.65%) slept ≤6 hours per day, 2 088 (43.17%) slept >6-8 hours per day, and 976 (20.18%) slept >8 hours per day. The detection rate of cognitive impairment was 37.44% (1 811/4 837). After adjusting for gender, age, living area, education level and other confounding factors, the detection rate of cognitive impairment was 1.26〔95%CI (1.09, 1.46) 〕 times higher in older adults with nighttime sleep duration of ≤6 hours, and was 1.22〔95%CI (1.03, 1.46) 〕 times higher in older adults with nighttime sleep duration of >8 hours than in those with nighttime sleep duration of >6-8 hours (P<0.05). The detection rate of cognitive impairment in male older adults with nighttime sleep duration of >8 hours was 1.35〔 (95%CI (1.06, 1.72) 〕 times higher than in those with nighttime sleep duration of >6-8 hours (P<0.05). The detection rate of cognitive impairment in female older adults with nighttime sleep duration of≤6 hours was 1.29〔95%CI (1.06, 1.58) 〕 times higher than in those with nighttime sleep duration of >6-8 hours (P<0.05). The restriction cube spline curve showed an approximate U-shaped relationship between nighttime sleep duration and the risk for cognitive impairment, with the lowest risk at 7 hours. Conclusion Both shorter and longer nighttime sleep duration may be independent and dose-dependent risk factors for cognitive impairment in older adults. The optimal sleep time is about 7 hours. The association between longer sleep duration and cognitive impairment is pronounced in males, while the association between shorter sleep duration and cognitive impairment is pronounced in females.
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