Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) and obstructive sleep apnea (OSA) share overlapping metabolic and inflammatory pathways, yet population-level evidence linking MASLD and incident OSA remains limited. Using a nationwide cohort of 265,452 Korean adults aged ≥ 40 years, we evaluated OSA risk across five mutually exclusive phenotypes defined by steatosis (fatty liver index [FLI] ≥ 30), cardiometabolic risk factors (CMRFs), and alcohol intake: no steatotic liver disease (SLD) without CMRFs, no SLD with CMRFs, MASLD without alcohol, MASLD with alcohol intake below the metabolic-associated alcohol-related liver disease (MetALD) threshold (men < 210 g/week, women < 140 g/week), and MetALD. During a mean follow-up of 9.5 years, 1,025 participants developed OSA. Compared with the reference group, adjusted hazard ratios (aHRs) for OSA were 1.18 (95% confidence intervals [CI] 0.93-1.50) in individuals with CMRFs alone, 1.46 (95% CI 1.12-1.91) in MASLD without alcohol, 1.52 (95% CI 1.17-1.98) in MASLD with alcohol, and 1.40 (95% CI 1.01-1.94) in MetALD. Model-based absolute risk differences (ARDs) at 9.5 years showed consistent patterns (+ 0.05%, + 0.14%, + 0.16%, and + 0.12%, respectively). Sensitivity analyses using stricter steatosis criteria (FLI ≥ 60 or hepatic steatosis index ≥ 36) demonstrated a clearer dose-related gradient, with progressively higher OSA risk across MASLD without alcohol, MASLD with alcohol, and MetALD. These findings highlight MASLD-particularly alcohol-associated phenotypes-as important risk markers for OSA and underscore the need for targeted screening and early intervention strategies in this increasingly prevalent population.