← All sources
Long sleep duration and health outcomes: A systematic review, meta-analysis and meta-regression
Systematic review and meta-analysis of 137 prospective cohorts (>5.1 million participants) comparing long sleep with normal sleep: long sleep was associated with higher mortality (RR 1.39) and higher incidence of diabetes, cardiovascular disease, stroke, coronary heart disease, and obesity in pooled adjusted models.
Design
- SR + MA + meta-regression of prospective cohorts
- 137 studies; >5,134,036 participants (abstract)
- Exposure: long sleep vs normal duration
Pooled adjusted risk ratios (abstract)
- All-cause mortality: RR 1.39 (95% CI 1.31–1.47)
- Diabetes mellitus: 1.26 (1.11–1.43)
- Cardiovascular disease: 1.25 (1.14–1.37)
- Stroke: 1.46 (1.26–1.69)
- Coronary heart disease: 1.24 (1.13–1.37)
- Obesity: 1.08 (1.02–1.15)
- Hypertension: 1.01 (0.95–1.07) — not significant
Meta-regression
Abstract reports significant linear associations between longer sleep and mortality and incident CVD.
Evidence hygiene
Same observational caveats as short-sleep syntheses—hypersomnia, illness-related long time-in-bed, and depression overlap require cautious causal language.
Publication
Jike M, Itani O, Watanabe N, et al. Sleep Med Rev. 2018 Jun;39:25-36. PMID 28890167.
Outcomes
- All-Cause Mortality RiskEvents: /
- Long sleep vs normal: stroke RR 1.46 (95% CI 1.26-1.69); diabetes RR 1.26 (1.11-1.43); obesity RR 1.08 (1.02-1.15); hypertension not significant (RR 1.01, 0.95-1.07) per abstract.