Causal association between sleep duration, daytime napping, sleep disorders and ischemic heart disease: A systematic review and meta‑analysis of Mendelian randomization studies

Ischemic heart disease (IHD) is a disease with high mortality and disability. Numerous studies have established a significant correlation between IHD and sleep. This study aims to evaluate the quality of existing Mendelian randomization (MR) studies and integrate the results to provide an overview of the latest evidence on the causal relationship between sleep patterns and IHD. We conducted a comprehensive search of PubMed, Embase and Web of Science to identify MR studies related to IHD and sleep. Studies from database inception to September 9, 2024 were included. Following data extraction, we performed a rigorous quality evaluation and meta-analysis. Quality assessment was conducted through the Strengthening the Reporting of Observational Studies in Epidemiology using Mendelian Randomization (STROBE-MR) guidelines. Finally, we included 13 articles in the study. According to the quality assessment, the overall quality of the included literature was moderate. Meta-analysis showed that short sleep duration (≤6h, OR:1.22[1.16,1.28]; P < 0.001, I² = 46.7 %), daytime napping (OR:1.63[1.26,2.12]; P < 0.001, I² = 0.0 %), and sleep disorders (OR:1.44[1.29–1.60]; P < 0.001, I² = 85.4 %) were positively associated with IHD, while extending sleep duration had a protective effect on IHD (OR:0.77[0.71,0.83]; P < 0.001, I² = 0.0 %). These findings show the effect of sleep on IHD. Short sleep duration, daytime napping and sleep disorders increase the risk of IHD, and whereas extending sleep duration is beneficial for reducing the risk of IHD.