The relationship between sleep duration and all-cause mortality in the older people: an updated and dose-response meta-analysis

Abstract Background: Short or long sleep duration is proposed as a potential risk factor for all-cause mortality in the older people, yet the results of published studies are not often reproducible. Objectives: We aimed to investigate whether short or long sleep duration was associated with an increased risk of all-cause mortality in the older people via a comprehensive meta-analysis. Methods: Literature retrieval, study selection and data extraction were completed independently and in duplicate. Effect-size estimates are expressed as relative risk (RR) and its 95% confidence interval (CI). Results: Summary data from 35 articles, involving a total of 106990 older people, were meta-analyzed. Overall analyses revealed a significant association between long sleep duration and all-cause mortality (RR=1.27, 95% CI: 1.19-1.35, P <.001), whereas marginal significance was observed for short sleep duration (RR=1.05; 95% CI: 1.00-1.09; P =.045). There was a low probability of publication bias as indicated by Egger’s test for the association between sleep duration and all-cause mortality. In subgroup analyses, the association between long sleep duration and all-cause mortality was relatively strong in women (RR=1.48, 95% CI: 1.18-1.85, P =.002) relative to men (RR=1.30, 95% CI: 1.10-1.50, P =.001) (Two-sample Z test P = .219). Further dose-response regression analyses showed that trend estimation was not obvious for short sleep duration ( P = .016) compared with long sleep duration ( P < .001), indicating a J-shaped relationship between sleep duration and all-cause mortality. Conclusions: Our findings indicate a J-shaped relationship between sleep duration and all-cause mortality in the older people, with long sleep duration significantly associating with all-cause mortality, especially in women.