Sleep habits and the risk of physical, psychological and cognitive multimorbidities: a national prospective cohort study

BACKGROUND: Physical, psychological, and cognitive multimorbidity (PPC-MM), defined as the coexistence of conditions in at least two domains of physical conditions, depressive symptoms, and cognitive impairment, poses a major challenge to healthy aging. However, its potential risk factors remain unclear. As a key component of health, sleep habits are closely associated with various chronic conditions. This study aimed to investigate the longitudinal associations between sleep habits (night-time sleep duration, nap duration, and sleep quality) and the occurrence and progression of PPC-MM. METHODS: We enrolled 7586 participants aged ≥45 years from the China Health and Retirement Longitudinal Study (CHARLS). All participants had no PPC-MM at baseline and provided self-reported data on sleep habits. The relationships between sleep habits and PPC-MM were evaluated using Cox proportional hazards regression and multi-state models. RESULTS: Over a 7-year follow-up, 3239 participants (42.6%) developed PPC-MM. Short night-time sleep (<7 h/night) and poor sleep quality (>1 d/week) were related to a higher risk of incident PPC-MM, with the strongest associations observed for sleeping <5 h/night (HR = 1.52, 95% CI: 1.37-1.70) and restless sleep on 5-7 d/week (HR = 1.47, 95% CI: 1.32-1.62). PPC-MM risk showed a U-shaped relationship with night-time sleep duration. In addition, joint associations of sleep duration and sleep quality on PPC-MM were observed. Multi-state model revealed very short night-time sleep (<5 h/night) and poor sleep quality (>1 d/week) were related to transitions from baseline to dual-domain comorbidity, whereas frequent restless sleep (5-7 d/week: HR = 1.40, 95% CI: 1.06-1.86) were associated with direct transition to triple-domain multimorbidity. CONCLUSION: Short night-time sleep duration and poor sleep quality were associated with an elevated risk of PPC-MM incidence and progression, with evidence of a joint adverse association. Such disturbances may serve as early indicators of PPC-MM risk. These findings suggest that sleep habits may serve as potential risk markers of multidomain health deterioration, thereby informing strategies to support healthy aging in middle-aged and older adults.