Sleep Disorders and Nonalcoholic Fatty Liver Disease: Evidence From Meta-Analysis and Mendelian Randomization

Background Sleep disorders and Non-alcoholic Fatty Liver Disease (NAFLD) bare both highly prevalent globally. But the relationships between them remain unclear. So we aimed to explore the impact of sleep disorders on NAFLD risk. Methods Using a combination of meta-analysis and Mendelian Randomization (MR), we investigated the associations between three common sleep disorders and NAFLD, including insomnia, obstructive sleep apnea (OSA) and narcolepsy. For meta-analysis, we systematically searched PubMed, Web of Science and Embase up to July 3, 2024. Ultimately, 13 studies were included, encompassing a total of 537,497 participants. Subsequently, MR analyses were performed to explore the causal relationships between each of the three sleep disorders and NAFLD. Results The meta-analysis revealed that insomnia (OR = 1.40, 95% CI: 1.05-1.87), OSA (OR = 2.15, 95% CI: 1.47-3.13) and narcolepsy (OR = 1.38, 95% CI: 1.05-1.80) were all associated with an elevated NAFLD risk. Moreover, MR analysis indicated a causal relationship between OSA and NAFLD (OR = 1.19, 95% CI: 1.04-1.37, P = 0.042). However, the strong evidence of the causal relationships between narcolepsy or insomnia and NAFLD was not found. Conclusion In this study, meta-analysis results indicate a significant link between the three common sleep disorders (insomnia, OSA, narcolepsy) and increased NAFLD risk. MR analysis suggests a causal relationship between OSA and NAFLD. However, there's no sufficient evidence for causal links of both narcolepsy and insomnia with NAFLD.