Association of Sleep Duration with MASLD Status and Hepatic Steatosis Index in Korean Adults: The Indirect Role of Sedentary Behavior.

Abstract

Purpose: Metabolic dysfunction-associated steatotic liver disease (MASLD) affects nearly three in ten adults globally, while its prevalence in South Korea has risen by approximately 3-4% per year. Although MASLD is linked to lifestyle factors, few studies have examined the associations among sleep duration, MASLD status, and the hepatic steatosis index (HSI). Accordingly, we evaluated the relationship between sleep duration and MASLD status and separately assessed whether sedentary behavior formed an indirect pathway between sleep duration and HSI, an indicator of hepatic steatosis.

Methods: The analysis included 26,909 adults aged 20 years or older who participated in the Korea National Health and Nutrition Examination Survey from 2014 through 2021. Logistic regression was used to estimate the relationship of sleep duration with MASLD status. Mediation analysis was conducted using HSI as the outcome variable to examine whether sedentary behavior indirectly linked sleep duration with HSI.

Results: MASLD was identified in 23.2% of 26,909 participants. In the adjusted logistic model, MASLD odds were higher among participants sleeping ≤4 hours (OR = 1.44, 95% CI: 1.17-1.78) and those reporting ≥8 hours of sedentary time (OR = 1.17, 95% CI: 1.09-1.25). Correlations of HSI with sleep duration (r = -.06, p < .001) and sedentary behavior (r = .02, p < .001) were small. The mediation model yielded a direct association between sleep duration and HSI (β = -0.21, 95% CI: -0.26 to -0.16), whereas the indirect effect through sedentary behavior was statistically significant but minimal (β = -0.0073, 95% bootstrap CI: -0.0118 to -0.0032).

Conclusion: MASLD status was related to both shorter sleep and longer sedentary time. Nevertheless, the very small correlations among sleep duration, sedentary behavior, and HSI offered little empirical support for a meaningful mediation pathway. Longitudinal research is required to establish the direction and timing of these relationships.