Evaluating the causal connections between sleep duration and disease prevalence: A comprehensive systematic review and meta-analysis of Mendelian randomization studies

BACKGROUND: The causal link between sleep duration and diverse health conditions remains unconfirmed. This meta-analysis aimed to clarify these relationships by synthesizing Mendelian randomization (MR) study evidence. METHODS: PubMed was systematically searched up to February 15, 2024, for MR studies exploring genetic predispositions to sleep duration/insomnia (short/long/overall sleep duration, insomnia) and associations with circulatory, digestive, neurodegenerative, metabolic diseases, and cancers. Eligible effect estimates were meta-analyzed. RESULTS: Fifty-one MR studies were included. Genetic variations in sleep traits were strongly linked to elevated risk of 12 cardiovascular diseases, obesity-related metrics (Type 2 diabetes, fasting glucose/insulin, HbA1c), neurological disorders (Alzheimer, amyotrophic lateral sclerosis, Parkinson disease), mental health conditions (attention-deficit/hyperactivity disorder, autism, bipolar disorder, major depressive disorder, schizophrenia), inflammatory bowel disease, and lung cancer. CONCLUSION: Genetic evidence confirms causal associations between sleep characteristics and multiple diseases, emphasizing sleep's key role in health promotion and supporting personalized sleep management to reduce disease risk.