Poor sleep quality increases mortality risk: A population-based longitudinal prospective study in community-dwelling middle-aged and older adults

Objectives: To assess the association between sleep quality and all-cause mortality in community-dwelling adults living in rural Ecuador. Methods: Individuals aged ≥40 years enrolled in the prospective population-based Three Villages Study cohort were included. Sleep quality was assessed by means of the Pittsburgh Sleep Quality Index. Study participants were evaluated at baseline and at every annual door-to-door survey until they remained enrolled in the study. Mixed models Poisson regression for repeated Pittsburgh Sleep Quality Index determinations and multivariate Cox-proportional hazards models were fitted to estimate mortality risk according to sleep quality. Results: Analysis included 1494 individuals (mean age: 56.6 ± 12.5 years; 56% women) followed for a median of 6.3 ± 3.3 years. At baseline, 978 (65%) individuals had good sleep quality and 516 (35%) had poor sleep quality. The effects of Pittsburgh Sleep Quality Index scores changing over time on mortality was confounded by the impact of the SARS-CoV-2 pandemic on both. One hundred ninety-five individuals (13%) died during the follow-up, resulting in a crude mortality rate of 1.58 per 100 person years (95% C.I.: 1.27-1.88) for individuals with good sleep quality, and 3.18 (95% C.I.: 2.53-3.82) for those with poor sleep quality at baseline. A multivariate Cox-proportional hazards model showed that individuals with poor sleep quality at baseline were 1.38 times (95% C.I.: 1.02-1.85) more likely to die compared to those with good sleep quality; in this model, increased age, poor physical activity, and high fasting glucose remained significant. Conclusions: Poor sleep quality is associated with increased mortality risk among middle-aged and older adults.