Relationship of Sleep Duration With All-Cause Mortality and Cardiovascular Events: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of prospective cohort studies for an etiological/prognostic question
PubMed 28889101 · doi:10.1161/JAHA.117.005947
What was done
PubMed and Embase were systematically searched through December 1, 2016, for prospective cohort studies examining the dose-response associations between sleep duration and risk of all-cause mortality, total cardiovascular disease (CVD), coronary heart disease (CHD), and stroke in generally healthy populations.
What was found
A U-shaped association was observed for all outcomes, with the lowest risk at approximately 7 hours of sleep per day regardless of sex. - All-cause mortality: For <7 hours/day, pooled relative risk (RR) was 1.06 (95% CI, 1.04–1.07) per 1-hour reduction; for >7 hours/day, pooled RR was 1.13 (95% CI, 1.11–1.15) per 1-hour increment. - Total CVD: Pooled RR was 1.06 (95% CI, 1.03–1.08) per 1-hour reduction and 1.12 (95% CI, 1.08–1.16) per 1-hour increment. - Coronary heart disease: Pooled RR was 1.07 (95% CI, 1.03–1.12) per 1-hour reduction and 1.05 (95% CI, 1.00–1.10) per 1-hour increment. - Stroke: Pooled RR was 1.05 (95% CI, 1.01–1.09) per 1-hour reduction and 1.18 (95% CI, 1.14–1.21) per 1-hour increment.
Why it matters
This meta-analysis quantifies a consistent U-shaped risk curve, establishing 7 hours per day as the reference nadir for cardiovascular and all-cause mortality risk.
Limits
The abstract does not state the number of included studies, overall participant sample size, or follow-up durations. Because the underlying data come from observational cohort studies, residual confounding and reverse causation (e.g., pre-existing subclinical disease causing longer sleep duration) cannot be excluded, and sleep duration was likely assessed via self-report rather than objective actigraphy or polysomnography.
Cited by
- supports Sleeping fewer than 7 hours per night or more than 10 hours per night is associated with increased all-cause mortality compared to sleeping 7 to 9 hours.