1Department of Medicine and Rehabilitation, Policlinico di Monza, Monza, Italy.
2Department of Medicine and Surgery, University of Milano Bicocca, Milan, Italy.
Data are limited on the epidemiology of fibrotic non-alcoholic steatohepatitis (NASH). We applied the recently proposed Fibrotic NASH Index (FNI) to estimate trends in the prevalence of probable fibrotic NASH in the general United States population using data from the 1999-2016 cycles of the National Health and Nutrition Examination Survey. A total of 40 273 participants aged 20 years and older were included in the analysis. The prevalence of probable fibrotic NASH (FNI ≥0.33) in the overall population was 8.4% (95% CI 8.0-8.8), with higher values found in males and in Hispanic participants. It increased from 6.9% (95% CI 6.3-7.6) in 1999-2004 to 9.2% (95% CI 8.4-10.0) in 2011-2016. This positive trend was evident in both sexes and in participants with obesity and diabetes. Finally, it increased progressively with increasing age, body mass index and worse glucose tolerance. NASH prevalence is increasing in the general US population, synchronous with increasing rates of obesity and type 2 diabetes.