Research Links Insomnia to Increased Risks of Stroke and Dementia

The review, funded by the European Academy of Neurology, compiles evidence addressing various health outcomes. In addition to the heightened risks of stroke and hospitalization, insomnia was found to correlate with depression and suicidal behaviors, and evidence suggests a connection with dementia, particularly Alzheimer's disease.

Insomnia, characterized by difficulty falling or staying asleep despite having the opportunity for rest, can severely impair daytime functioning. A previous meta-analysis indicated that approximately 22% of the general population meets the international diagnostic criteria for insomnia.

Lead author Luca Vignatelli from the IRCCS Istituto delle Scienze Neurologiche in Bologna, Italy, remarked that insomnia should be viewed as a warning signal for brain and mental health. Vignatelli emphasized that individuals with insomnia face increased risks for conditions such as dementia and stroke, highlighting the necessity of addressing insomnia as part of a comprehensive health strategy.

To explore the broader health implications of insomnia, researchers reviewed data from two major medical databases, MEDLINE and EMBASE, up until August 2025. They integrated evidence from existing systematic reviews with new studies examining strokes, occupational injuries, and hospitalizations.

For the stroke analysis, nine studies were deemed eligible, with six included in the meta-analysis that encompassed over 1.3 million participants. The review discovered that individuals with insomnia had a 26% higher risk of stroke (HR 1.26; 95% CI 1.05–1.53), though the strength of this association varied among studies.

In the assessment of hospitalizations, five studies were analyzed, three of which were included in the meta-analysis. The results indicated that those with insomnia had 28% higher odds of being hospitalized for any reason (OR 1.28; 95% CI 1.14–1.43).

Furthermore, the broader evidence established relationships linking insomnia to several brain and mental health conditions. Most reviews pointed to an association between insomnia and all-cause dementia, though findings were inconsistent. The connection with Alzheimer's disease was clearer, while findings related to vascular dementia were more varied.

The authors caution that these findings should be understood considering the differing definitions of insomnia used in various studies and the minimal focus on sleep medication usage. They highlight that the review indicates associations but does not confirm that insomnia directly causes the studied conditions. Nonetheless, the results advocate for increased attention to insomnia in clinical settings and for the inclusion of sleep disorders and sleep hygiene in health promotion efforts.

Professor Stefan Seidel, a co-author of the study, stated that sleep should be a key topic in discussions on brain health across all ages. He called for heightened awareness regarding insomnia and its treatment, advocating for the integration of sleep considerations into health promotion programs in communities, schools, and workplaces.