Association of nonalcoholic fatty liver disease with new-onset atrial fibrillation stratified by age groups

The association between nonalcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) has been inconsistent, and the impact of hepatic fibrosis on this relationship remains uncertain. We investigated the association between NAFLD and the risk of new-onset AF across different age groups. A total of 3,179,582 participants from the 2009 Korean National Health Screening Program were divided into five groups based on NAFLD status: no NAFLD (fatty liver index [FLI] < 30); grade 1 NAFLD without advanced fibrosis (FLI 30–59 & BARD < 2); grade 1 NAFLD with advanced fibrosis (FLI 30–59 & BARD ≥ 2); grade 2 NAFLD without advanced fibrosis (FLI ≥ 60 & BARD < 2); and grade 2 NAFLD with advanced fibrosis (FLI ≥ 60 & BARD ≥ 2). The primary outcome was incident AF. During the median follow-up of 9.3 years, 62,542 patients were diagnosed with new-onset AF. In the age- and sex-adjusted model, the risk of new-onset AF increased across NAFLD grades and fibrosis categories: grade 1 NAFLD without advanced fibrosis (hazard ratio [HR] 1.120, 95% confidence interval [CI]: 1.081–1.161); grade 1 NAFLD with advanced fibrosis (HR 1.275, 95% CI 1.251–1.300); grade 2 NAFLD without advanced fibrosis (HR 1.305, 95% CI: 1.252–1.360); and grade 2 NAFLD with advanced fibrosis (HR 1.627, 95% CI: 1.586–1.670). In the multivariate model, the excess risk of AF in patients with NAFLD and advanced fibrosis remained significant, even in participants aged 20–39 years. Patients with NAFLD had a higher risk of new-onset AF, which increased progressively with NAFLD severity, particularly in those aged 20–29 years.