Sleep patterns, global mental status and mortality risk among middle-aged urban adults.

BACKGROUND

Sleep, cognition, and mortality may be interdependent.

OBJECTIVE

We explored paths between sleep, cognition and mortality and potential interactions.

METHODS

The study examines the relationship among sleep, global mental status, and mortality risk using data from 1364 participants from the Healthy Aging in Neighborhood of Diversity across the Life Span (HANDLS) study. We used Cox proportional hazards models and four-way decomposition models to analyze sleep patterns and global mental status.

RESULTS

After a median time at risk of 8.2 years, 172 deaths occurred, with rate of 16 per 1000 person-years. A 1-unit increase in the Pittsburgh Sleep Quality Index (PSQI) global score was linked to a 7% increase in mortality risk in the reduced model, but this effect was attenuated in the full model. In both reduced and fully adjusted models, the PSQI global score and sleep quality domains interacted with global mental status, with poor sleep generally associated with mortality risk in the group with better global mental status at first-visit. In four-way decomposition models, total effects (TE) of PSQI scores on mortality risk were positive and statistically significant, while being mostly controlled direct effects. However, among women, the inverse TE of global mental status on mortality risk was partially mediated by PSQI sleep latency and the PSQI global.

CONCLUSIONS

Poor global mental status is associated with greater mortality risk at better sleep quality levels and vice versa. Further longitudinal studies with multiple sleep and cognitive performance repeats are needed to corroborate these findings.