The association between sleep disorder and stroke risk: A meta-analysis of observational studies

Background: Sleep disturbances, including insomnia and obstructive sleep apnea (OSA), have been increasingly linked to cardiovascular diseases. However, their relationship with stroke risk remains controversial. While some studies suggest a strong association, others show limited or no correlation. This meta-analysis synthesizes observational data to assess the association between sleep disorders and stroke risk, aiming to provide clearer insights into this critical public health concern. Methods: A systematic review and meta-analysis were conducted following PRISMA guidelines. A comprehensive search of PubMed, NIH, Scopus, and Google Scholar yielded 1,284 articles, of which 10 studies, including 514 participants, met the inclusion criteria. Studies included were cohort, case-control, or cross-sectional, with adequate statistical power to report risk estimates for stroke associated with sleep disorders. Two independent investigators performed data abstraction and quality assessment using the Newcastle-Ottawa Scale. The DerSimonian-Laird random-effects model was used to calculate pooled relative risks (RRs), with heterogeneity quantified using the I² statistic. Publication bias was assessed through funnel plots and Egger's test. Results: Sleep disorders were significantly associated with an increased risk of stroke, with a pooled RR of 1.82 (95% CI: 1.45-2.30, p < 0.001). Among subgroups, OSA posed the highest risk (RR: 2.17, 95% CI: 1.64-2.89), followed by insomnia (RR: 1.47, 95% CI: 1.12-1.92). High heterogeneity was observed across studies (I² = 76%), largely attributed to variations in study design, diagnostic criteria, and participant characteristics. Sensitivity analyses confirmed the robustness of the findings, and no significant publication bias was detected. Conclusions: This meta-analysis provides compelling evidence that sleep disorders, particularly OSA and insomnia, are strongly associated with an increased risk of stroke. Given the high prevalence of sleep disturbances, incorporating sleep disorder screenings into routine cardiovascular evaluations could significantly enhance stroke prevention strategies. Future research should explore the mechanisms underlying this association and evaluate the efficacy of targeted interventions in reducing stroke risk.