SLEEP DURATION AND ALL CAUSE-MORTALITY IN 1.3 MILLION PEOPLE WITH OVER 100,000 FATAL EVENTS: PP.32.276

Abstract

Background: Increasing evidence suggests an association between both short and long duration of habitual sleep with adverse health outcomes. Objectives: To assess whether the population longitudinal evidence supports the presence of a relationship between duration of sleep and all-cause mortality, to investigate both short and long sleep duration and to obtain an estimate of the risk. Methods: We performed a systematic search of publications using MEDLINE (1966–2009), EMBASE (from 1980), the Cochrane Library and manual searches without language restrictions. We included studies if they were prospective, had follow up >3 years, had duration of sleep at baseline and all-cause mortality prospectively. We extracted relative risks (RR) and 95% C.I. and pooled them using a random effect model. We carried out sensitivity analyses and assessed heterogeneity and publication bias. Results: Overall, the 16 studies analysed provided 27 independent cohort samples. They included 1,382,999 male and female participants (follow-up range 4 to 25 years), and 112,566 deaths. Sleep duration was assessed by questionnaire and outcome through death certification. In the pooled analysis, short duration of sleep was associated with a greater risk of death (RR: 1.12; 95% CI 1.06 to 1.18; p < 0. 01) with no evidence of publication bias (p = 0.74) but heterogeneity between studies (p = 0.02). Long duration of sleep was also associated with a greater risk of death (1.30; [1.22 to 1.38; p<0.0001) with no evidence of publication bias (p = 0.18) but significant heterogeneity between studies (p < 0.0001). For short sleep, the effect was consistent across genders, age and socio-economic groups, and when stratified by duration of sleep, follow-up or location. For long sleep, the effect was stronger in older cohorts (p = 0.01), in longer duration of sleep (p = 0.0004), in East Asian cohorts (p = 0.01) and weaker in follow-ups >20 years (p = 0.01). Conclusion: Both short and long duration of sleep are significant predictors of death in prospective population studies.