Sleep characteristics associated with mild cognitive impairment among rural‐dwelling older adults: The MIND‐China study

Abstract

AbstractBackgroundSleep characteristics associated with mild cognitive impairment (MCI) and its subtypes are poorly defined in old age. We sought to characterize the sleep disturbances associated with MCI, subtypes of MCI, and specific cognitive domains among rural‐dwelling older adults in China.MethodThis population‐based cross‐sectional study included 4469 participants (age ≥65 years, 56.4% women) who were free of dementia and living in the rural communities in Yanggu County, Shandong. We collected data through interviews, clinical examinations, neuropsychological testing, and laboratory tests. We used the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale to evaluate various sleep parameters. Specific domain of cognitive function were assessed with the Auditory Verbal Learning Test (immediate recall, long‐delayed free recall, and long‐delayed recognition) for memory, the Semantic Verbal Fluency Test for language, the Digit Span Test for attention, and the Trail Making Test A & B for executive function. MCI was diagnosed according to the Petersen’s criteria. Data were analysed using logistic and general linear regression models.ResultMCI was diagnosed in 1204 participants (940 with amnestic MCI [aMCI], 264 with nonamnestic MCI [naMCI]). The multivariable‐adjusted odds ratio (OR) of MCI was 1.45 (95% CI 1.14‐1.83) for sleep duration ≤4 hours/night (vs. >6‐8 hours/night), 1.39 (1.12‐1.72) for sleep duration >8 hours/night, 1.23 (1.06‐1.43) for poor sleep quality, 1.46 (1.25‐1.70) for low sleep efficiency, 1.29 (1.10‐1.50) for prolonged sleep latency, and 1.49 (1.17‐1.88) for excessive daytime sleepiness (EDS). These sleep characteristics were significantly associated with aMCI (multi‐adjusted OR range: 1.27‐1.46; p<0.05). EDS was significantly associated with naMCI (multi‐adjusted OR 1.56 [1.04‐2.33]). In addition, short and long sleep duration, poor sleep quality, low sleep efficiency, prolonged sleep latency, and EDS were associated with worse memory function. Long sleep duration, low sleep efficiency, and EDS were associated with worse language function. Low sleep efficiency and EDS were associated with worse attention function. However, none of the examined sleep parameters was significantly associated with executive function.ConclusionShort and long sleep duration, poor sleep quality, low sleep efficiency, prolonged sleep latency, and EDS were associated with an elevated likelihood of MCI, especially aMCI and poor memory function.