Insomnia symptoms were associated with a greater likelihood of ischemic stroke but not consistently with overall stroke risk, according to a systematic review and meta-analysis published in Sleep Medicine: X.
Researchers analyzed 17 studies—including 12 observational studies and five Mendelian randomization studies—representing 7,696,920 patients. Searches were conducted in PubMed, Embase, Scopus, Google Scholar, and Web of Science through March 2024.
In pooled analyses of cohort-based data using hazard ratios, insomnia symptoms were not statistically associated with all stroke types combined. However, patients with insomnia symptoms had a 7% greater likelihood of ischemic stroke, with no association observed for hemorrhagic stroke.
Separate pooled analyses using odds ratios showed a different pattern: insomnia symptoms were associated with higher odds of both all stroke types combined and ischemic stroke, highlighting variability across study designs.
Associations were stronger when insomnia was clinically diagnosed. Diagnosed insomnia was associated with a 45% greater likelihood of ischemic stroke and was also linked to an increased likelihood of any stroke. The researchers rated the certainty of evidence as high for insomnia symptoms and ischemic stroke and moderate for diagnosed insomnia and stroke outcomes.
Mendelian randomization analyses did not show a statistically significant association between insomnia symptoms and overall stroke risk but suggested a small association with ischemic stroke, with substantial heterogeneity across studies.
The researchers noted several limitations, including heterogeneity in insomnia definitions, reliance on self-reported questionnaires, and limited generalizability because most studies were conducted in high- and middle-income countries. They also noted that individual insomnia symptom subtypes—such as sleep maintenance insomnia vs nonrestorative sleep—could not be evaluated separately.
“Our results did not show a significant association between insomnia symptoms and all types of strokes; however, a higher risk of developing ischemic stroke was observed in the group with insomnia symptoms,” wrote Miguel Cabanillas-Lazo, of Universidad Científica del Sur in Lima, Peru, and colleagues.
The researchers emphasized the need for additional studies in low-income settings, noting that none of the included studies were conducted in Latin America despite evidence of high insomnia prevalence in that region.
The researchers concluded that future studies using objective sleep measures and more diverse populations may help clarify the relationship between insomnia and stroke risk.
The study received no specific funding. The researchers reported no competing interests.
Source: Sleep Medicine: X
