Associations between insomnia and cardiovascular diseases: a meta-review and meta-analysis of observational and Mendelian randomization studies.

Study objectives: Observational studies suggest associations between insomnia and cardiovascular diseases (CVDs), but the causal mechanism remains unclear. We investigated the potential causal associations between insomnia and CVDs by a combined systematic meta-review and meta-analysis of observational and Mendelian randomization (MR) studies.

Methods: We searched PubMed, Web of Science, and Embase for English-language articles from inception to 7/11/2023. Two reviewers independently screened the articles to minimize potential bias. We summarized the current evidence on the associations of insomnia with coronary artery disease (CAD), atrial fibrillation (AF), heart failure (HF), myocardial infarction (MI), hypertension (HTN), and stroke risk by combining meta-analyses of observational and MR studies.

Results: Four meta-analyses of observational studies and 9 MR studies were included in the final data analysis. A systematic meta-review of observational studies provided strong evidence that insomnia is an independent risk factor for many CVDs, including AF, MI, and HTN. A meta-analysis of MR studies revealed that insomnia may be potentially causally related to CAD (odds ratio (OR)=1.14, 95% confidence interval (CI)=1.10-1.19, I²=97%), AF (OR=1.02, 95% CI=1.01-1.04, I²=94%), HF (OR=1.04, 95% CI=1.03-1.06, I² =97%), HTN (OR=1.16, 95% CI=1.13-1.18, I²=28%), large artery stroke (OR=1.14, 95% CI=1.05-1.24, I²=0%), any ischemic stroke (OR=1.09, 95% CI=1.03-1.14, I²=60%), and primary intracranial hemorrhage (OR=1.16, 95% CI=1.05-1.27, I²=0%). No evidence suggested that insomnia is causally associated with cardioembolic or small vessel stroke.

Conclusions: Our results provide strong evidence supporting a possible causal association between insomnia and CVD risk. Strategies to treat insomnia may be promising targets for preventing CVDs.