Associations of sleep characteristics with mild cognitive impairment and dementia among Chinese elderly people living in a rural area: A population‐based study

Abstract

AbstractBackgroundSleep patterns might be changed in the early stage of the dementing process. Thus, sleep characteristics may be useful markers for identifying elderly persons at risk of mild cognitive impairment (MCI) and dementia. However, previous studies that investigated the associations of sleep characteristics and cognitive function have been scarcely conducted among Chinese older adults. We aim to determine the associations of various sleep characteristics with MCI and dementia among rural‐dwelling Chinese elderly people.MethodThis population‐based cross‐sectional study included 4680 participants who were aged ≥65 years and living in the rural communities in Yanggu County, Shandong Province. In March‐September 2018, we collected data through interviews, clinical examinations, cognitive testing, and laboratory tests. We used Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) to evaluate sleep characteristics such as sleep duration, sleep efficiency, and excessive daytime sleepiness (EDS). Cognitive function was assessed with a neuropsychological test battery. Dementia was diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria, and MCI was defined according to the modified Petersen’s criteria. Multiple multinomial logistic regression models were used to examine the associations of sleep characteristics with MCI or dementia.ResultOf the 4680 participants, 195 were diagnosed with dementia and 691 with MCI. Compare to the sleep duration of 4‐8 hours/night, the multivariable‐adjusted odds ratio (95% confidence interval) of MCI and dementia was 1.34 (1.01, 1.77) and 1.97 (1.25, 3.12) for very short sleep duration (≤4 hours/night), and 1.35 (1.06, 1.72) and 1.74 (1.11, 2.74) for long sleep duration (>8 hours/night). The EDS was significantly associated with the adjusted odds ratio of 1.36 (1.05, 1.78) for MCI and 1.80 (1.15, 2.84) for dementia. Moreover, low sleep efficiency was associated with an adjusted odds ratio of 1.65 (1.18, 2.30) for dementia and 1.10 (0.91, 1.33) for MCI.ConclusionLong and very short sleep duration and EDS were associated with an elevated likelihood of MCI and dementia among rural‐dwelling Chinese older adults. In addition, low sleep efficiency was associated with a high likelihood of dementia but not MCI.