The growing prevalence of nonalcoholic fatty liver disease (NAFLD), determined by fatty liver index, amongst young adults in the United States. A 20-year experience

Abstract

Aim: The Global burden of nonalcoholic fatty liver disease (NAFLD) has significantly increased recently, with its prevalence mirroring increasing obesity and diabetes. However, population-specific evidence for young adults remains limited. Herein, we provide a 20-year trend analysis of NAFLD in young adults and examine factors associated with NAFLD and major adverse cardiovascular events (MACE) prevalence. Methods: This study uses data from the United States National Health and Nutrition Examination Survey (NHANES) 1999-2018. Fatty liver was examined with the fatty liver index (FLI) and United States-FLI (US-FLI), and advanced fibrosis was examined with the fibrosis-4 index. Clustered multivariate logistic regression analysis on the year of study was applied to obtain odds ratios (OR) for the estimation of events. Results: 13.31% (95%CI: 12.71% to 13.94%) of young adults had NAFLD. The prevalence increased from 9.98% in 1999 to 19.49% in 2018, with a statistically significant trend (P < 0.001). 9.52% and 5.29% of patients have clinically significant and advanced fibrosis, respectively. In multivariate analysis, diabetes (3.48, 95%CI: 2.37 to 5.11), hypertension (2.03, 95%CI: 1.62 to 2.55), elevated body mass index (1.22, 95%CI: 1.20 to 1.23, P < 0.001) significantly increases odds of NAFLD. The largest increase in odds was related to obesity (OR: 21.61, 95%CI: 16.95 to 27.55, P < 0.001). Young adults with NAFLD had a borderline non-significant increase in the prevalence of MACE compared to individuals without NAFLD (OR: 1.603, 95%CI: 0.949 to 2.708, P = 0.078). Conclusion: The rising prevalence of NAFLD in young adults depicts the changing landscape of NAFLD and its association with a significant increase in MACE. The challenge of effective risk stratification and education of these individuals remains.