Differential effects of sleep duration on cardiovascular risk in metabolic-associated fatty liver disease vs. without metabolic-associated fatty liver disease: evidence from National Health and Nutrition Examination Survey and Mendelian randomization.

Background: Cardiovascular disease (CVD) risk increases in patients with metabolic-associated fatty liver disease (MAFLD). While sleep duration is linked to CVD risk, it is unclear whether it differs between individuals with and without MAFLD.

Methods: Data from the National Health and Nutrition Examination Survey (2007-2020; n = 10 386) were analyzed using multivariable logistic regression to examine the relationship between sleep duration and CVD. Subgroup analyses and a restricted cubic spline model assessed interactions and potential nonlinear associations, while Mendelian randomization (MR) was used to infer causality.

Results: Long sleep duration (≥9 h) was associated with an increased CVD risk in MAFLD patients [P = 0.005, odds ratio (OR) = 1.92, 95% confidence intervals (CI): 1.22-3.02], while short sleep duration (≤6 h) was linked to a higher CVD risk in non-MAFLD individuals (P = 0.030, OR = 1.63, 95% CI: 1.05-2.52). Subgroup analysis revealed that marital status modified this association in MAFLD patients. A U-shaped relationship was observed, with the lowest CVD risk occurring at 6.7 h of sleep for MAFLD patients and 7.9 h for non-MAFLD individuals. MR suggested a causal link (P = 0.03, OR = 1.42, 95% CI: 1.02-1.97), with the results remaining robust after adjusting for potential confounders.

Conclusion: Long sleep duration increases CVD risk in MAFLD patients, with a U-shaped relationship indicating the lowest risk at 6.7 h of sleep in MAFLD and 7.9 h in non-MAFLD individuals. MR analysis suggests a causal link between sleep duration and CVD.