The impact of the sleep duration on NAFLD score in Korean middle-aged adults: a community-based cohort study

Background: Accumulated evidences indicates that sleep duration and sleep quality may potentially trigger the development of non-alcoholic fatty liver disease (NAFLD), but no studies have explored this causality. In this study, we aimed to investigate the effect of sleep duration on the incidence of NAFLD in Korean middle-aged adults. Methods: All participants were selected from the cohort of the Korean Genome and Epidemiology Study (KoGES) for a 10-year period. NAFLD was defined by Fatty Liver Index (FLI), NAFLD liver fat score (NLFS), Hepatic Steatosis Index (HSI) and Lipid Accumulation Product (LAP). Multiple logistic regression analysis was used to assess the relationship between sleep duration and NAFLD defined by NAFLD scores. ANCOVA and Spline curve was also used to verify the differences in means of NAFLD scores according to the four sleep duration groups. Results: In comparison with those of individuals in the reference group, the OR (95% CI) for NAFLD was 2.230 (1.304-3.813) for group of people who slept more than 8 h, 1.869 (1.298-2.691) for 7-8 h after adjusting for several confounding factors. The odds ratio for the incidence of NAFLD was 1.462 (1.029 -2.077) for the group of people who sleep more than 8 h, 1.271 (1.001-1.615) for 7-8 h after adjusting for age, sex, BMI, SBP, DBP, TG, HDL, FDG, smoking, physical activity, daytime napping and night-time shifting (p < 0.01). Conclusion: These findings indicate a relationship between long sleep duration and the elevation of NAFLD scores and support the causality of sleep duration and incidence of NAFLD in Korean middle-aged adults. (c) 2019 Elsevier B.V. All rights reserved.