Inadequate sleep increases stroke risk: evidence from a comprehensive meta-analysis of incidence and mortality

The link between abnormal sleep duration and stroke outcomes remains contentious. This meta-analysis quantifies how both short and long sleep durations impact stroke incidence and mortality. A comprehensive search was conducted in PubMed, Web of Science, Cochrane Library, Embase, and Google Scholar up to November 1, 2024, to identify cohort studies evaluating sleep duration and stroke outcomes. Meta-analysis was performed using MetaAnalysisOnline.com and a random-effects model to estimate pooled hazard ratios (HRs). Results were visualized through Forest and Funnel plots. Analysis of 43 studies (35 on stroke incidence, 8 on mortality) revealed significant associations between sleep duration and stroke outcomes. Short sleep duration (≤ 5-6 h) was associated with increased stroke incidence (HR 1.29, 95% CI 1.19-1.40, p < 0.01) and modestly elevated mortality (HR 1.12, 95% CI 1.01-1.25, p = 0.03). Long sleep duration (> 8-9 h) demonstrated stronger associations with both increased stroke incidence (HR 1.46, 95% CI 1.33-1.60, p < 0.01) and mortality (HR 1.45, 95% CI 1.31-1.60, p < 0.01). Significant heterogeneity was observed in incidence studies (I2 = 74-75%), while mortality analyses showed moderate to low heterogeneity (I2 = 35-40%). This meta-analysis highlights a U-shaped association between sleep duration and stroke risk, with both short and long sleep durations linked to higher stroke incidence and mortality. These findings underscore the importance of balanced sleep duration as a modifiable risk factor in stroke prevention strategies and provide a foundation for the Semmelweis Study, a prospective workplace cohort investigating the role of modifiable lifestyle factors in unhealthy cerebrovascular and brain aging.