Nonalcoholic Fatty Liver Disease Increases the Risk of Lung Abscess: Findings from a Nationwide Cohort Study

The prevalence of non-alcoholic fatty liver disease (NAFLD) has become a issue in recent decades, prompting investigations into its connections with various infectious diseases. This study aimed to elucidate the potential association between NAFLD and the incidence of lung abscess within a large, population-based cohort. We evaluated 367,930 subjects without comorbidities who underwent the National Health check-ups between 2009 and 2018. NAFLD was determined using the Fatty Liver Index (FLI) as a surrogate marker. The relationship between FLI and the risk of lung abscess was examined using multivariate Cox proportional hazards models. Additionally, community-acquired pneumonia (CAP) was included as a control group in the analysis. A total of 44,934 (12.2%) and 455 (0.12%) patients were diagnosed with CAP and lung abscess, respectively. Participants were categorized into three groups according to FLI (FLI <30, 30≤ FLI <60, 60≥ FLI). The cumulative incidence of lung abscess was significantly higher in subjects with higher FLIs than those with lower FLIs (FLI <30, 0.10%; 30≤ FLI <60, 0.16%; 60≥ FLI, 0.18%; p<0.001). In the adjusted model, a higher FLI was independently associated with an increased incidence of lung abscess (HR for the highest vs. lowest FLI, 1.67; 95% CI 1.05-2.63; p=0.02). In conclusion, FLI remained significantly associated with a higher incidence of lung abscess, even after accounting for baseline participant characteristics. This study has provided compelling evidence supporting the association between NAFLD, as assessed by FLI, and an elevated risk of lung abscess. Physicians should be alert in monitoring patients with NAFLD in respiratory health.