Prevalence, characteristics and mortality outcomes of obese, nonobese and lean NAFLD in the United States, 1999–2016

BACKGROUND Updated prevalence and outcome data for nonobese NAFLD for the multi-ethnic US population is limited. OBJECTIVES We aimed to investigate the prevalence, clinical characteristics and mortality of obese and nonobese individuals with NAFLD in the United Sates. METHODS A retrospective study was conducted using the 1999-2016 NHANES databases. We determined hazard ratio stratified by obesity status in NAFLD individuals using Cox regression and log-rank test. RESULTS Overall NAFLD prevalence was 32.3%: 22.7% were obese and 9.6% were nonobese, with increasing trend over time for obese NAFLD, but not nonobese NAFLD. Amongst those with NAFLD, 29.7% (95% CI: 27.8%-31.7%) were nonobese, of which 13.6% had lean NAFLD. Nonobese NAFLD was more common in older (40.9% if ≥ 65 vs. 24.2% if