Association between non-alcoholic fatty liver disease and risk of new-onset atrial fibrillation in healthy adults

Background & aims: Previous studies demonstrated conflicting results regarding the association between non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF). The statistical power was not sufficient because of modest sample sizes of these studies. We analysed a large population-based cohort to evaluate the association between NAFLD and AF.

Methods: We evaluated 334 280 healthy individuals without comorbidities who underwent National Health check-ups in South Korea from 2009 to 2014. NAFLD was defined by a surrogate marker, the fatty liver index (FLI). The association between FLI and AF incidence was analysed using multivariate Cox proportional hazards regression models.

Results: During a median follow-up of 5.3 years, 1415 subjects (0.4%) were newly diagnosed with AF. Subjects were categorized into quartile groups according to FLI (range: Q1, 0-4.9; Q2, 5.0-12.5; Q3, 12.6-31.0; Q4, >31.0). The cumulative incidence of AF was significantly higher in subjects with higher FLIs than in those with lower FLIs (Q1, 167 [0.2%]; Q2, 281 [0.3%]; Q3, 470 [0.6%]; Q4, 497 [0.6%]; P < .001). Adjusted hazard ratios (HRs) indicated that a higher FLI was independently associated with an increased risk for AF (HR between Q4 and Q1, 1.35; 95% confidence interval [CI], 1.11-1.63; P = .002). After further adjustment for the interim events (diabetes, hypertension, heart failure and myocardial infarction), this association remained statistically significant (HR between Q4 and Q1, 1.55; 95% CI, 1.19-2.03; P = .001).

Conclusions: NAFLD, assessed by FLI, was independently associated with increased risk for AF in healthy Korean population. Moreover, NAFLD itself predisposes to AF independently of the interim events.