Longitudinal association of self-reported restless sleep and duration with motoric cognitive risk syndrome in Chinese older adults: Evidence from CHARLS.

BACKGROUND: Motoric cognitive risk syndrome is an established risk factor for dementia in older adults. Although self-reported sleep complaints and sleep duration have been cross-sectionally associated with MCR, prospective evidence remains limited. METHODS: Data were obtained from the 2011, 2013, and 2015 waves of the China Health and Retirement Longitudinal Study. We included older adults aged 60 and above. Restless sleep was assessed using a single self-reported item and categorized as rare (≤2 days/week), occasional (3-4 days/week), and frequent (5-7 days/week) restless sleep. Self-reported sleep duration was classified as <6 h/night, 6-8 h/night, and >8 h/night. Cox regression models were employed to estimate the association between self-reported restless sleep and duration and MCR. RESULTS: Among 3600 participants (median age, 66 years; 49.53% female), 338 participants developed MCR during a mean follow-up of 3.63 years. Compared with rare restless sleep, frequent restless sleep was associated with incident MCR (HR = 1.71, 95% CI: 1.06-2.76). Short sleep duration (<6 h/night) was also associated with increased MCR risk compared to 6-8 h/night (HR = 1.53, 95% CI: 1.03-2.27). Participants experiencing both frequent restless sleep and short sleep duration had a higher risk of incident MCR (HR = 2.00, 95% CI: 1.11-3.61) compared to those with rare restless sleep and 6-8 h/night sleep. Given the multiple comparisons performed, these findings should be considered exploratory. CONCLUSIONS: In this exploratory observational study, self-reported frequent restless sleep and short sleep duration were associated with incident MCR among community-dwelling older adults in China. Given the multiple comparisons without formal adjustment, limited sleep measurement, and potential residual confounding, these findings should be interpreted cautiously. Further prospective studies using validated multidimensional and objective sleep assessments are needed to examine these associations.