Mechanism of the association between sleep quality and mortality in middle-aged and older adults: A prospective study analysis of the UK Biobank

Abstract

Background: Although sleep quality is known to be associated with mortality, how poor sleep quality contributes to an increased risk of mortality is still unknown. We aimed to examine whether lifestyle, psychosocial and biological factors mediate the association.

Methods: 205,654 participants from UK Biobank were used for the analysis. The outcome was all-cause, cardiovascular disease (CVD) and cancer mortality by February 2022. Exposure was assessed by a sleep score consisting of five sleep behaviors at baseline. Lifestyle, psychosocial, and biological factors are regarded as potential mediators. Mediation analysis based on Cox proportional hazards models was performed.

Results: Poor sleep quality was associated with a higher risk of all-cause (Hazard Ratio [HR] = 1.098; 95% CI: 1.058-1.140), CVD (HR = 1.139; 95% CI: 1.045-1.243) and cancer mortality (HR = 1.095; 95% CI: 1.040-1.152). Lifestyle mediators (smoking, physical activity, sedentary, BMI and diet) could explain between 2.6% and 34.0% of the increased risk of all-cause mortality in individuals with poor sleep quality. Self-reported health, frailty, depression, and loneliness were significant psychosocial mediators of this association pathway. About one-fifth of the association can be explained by the biological role of CRP. Similar mediating patterns were observed for CVD and cancer mortality.

Limitations: Both exposure and mediators were measured at baseline, so the possibility of reverse causality cannot be ruled out.

Conclusions: Poor sleep quality is associated with an increased risk of death through a combination of lifestyle, psychosocial and biological pathways. Adopting healthy lifestyles and staying psychosocial well-being are cost-effective interventions to lower the risk of death.

Keywords: Biological; Lifestyle; Mediators; Mortality; Psychosocial; Sleep quality.