OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is one of the leading risk factors for liver cancer and liver transplant. However, most patients become aware of their disease in late stages. Our objective was to estimate the prevalence and factors associated with the diagnosis of NAFLD among adults in the United States from 1999 to 2020.

METHODS: We used National Health and Nutrition Examination Survey (NHANES) data from 1999-2020. A diagnosis of NAFLD was determined based on a United States Fatty Liver Index (USFLI) score of greater than 30. Individuals were excluded if they were under 18, pregnant, had hepatitis B/C, were missing variables utilized in the USFLI, or had evidence of heavy drinking. An individual was assumed to have NAFLD with advanced fibrosis if their FIB-4 score was greater than 2.67. A respondent’s awareness of their liver condition was established by their responses to the NHANES medical questionnaire. The associations between demographic factors and NAFLD awareness were tested using multivariate logistic regression.

RESULTS: Overall, as many as 32.4% (31.3-33.5%) of the U.S. adult population may have NAFLD, while only 4.9% (4.1-5.8%) are presently aware. 2.9% (2.5-3.3%) of U.S. adults may have NAFLD with advanced fibrosis, and among these individuals, 13.4% (9.4-17.4%) were aware of their condition. Individuals who were aware of their NAFLD were more likely to be Hispanic, OR=1.49 (1.00-2.22); Obese III, OR=2.60 (1.18-5.74); have a place for routine care, OR=3.20 (1.47-6.96); or have fibrosis, OR=3.14 (1.93-5.11) than those who were not aware. However, compared to white respondents, those who identified as non-Hispanic black were significantly less likely to be aware of their NAFLD, OR=0.39 (0.20-0.73).

CONCLUSIONS: Nearly one-third of U.S. adults may have NAFLD; however, only one in twenty are aware. Public health interventions are needed to increase NAFLD diagnosis.