Prevalence and factors associated with NAFLD detected by vibration controlled transient elastography among US adults: Results from NHANES 2017-2018.

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is increasingly common in the adult population. In the United States, the overall burden of NAFLD is unknown due to challenges with population-level NAFLD detection. The purpose of this study was to estimate prevalence of NAFLD and significant NAFLD fibrosis and identify factors associated with them in the U.S.

METHODS

Data came from the 2017-2018 cycle of National Health and Nutrition Examination Survey. We defined NAFLD by controlled attenuation parameter (CAP) scores of ≥248 dB/m in absence of excessive alcohol use and viral hepatitis. We defined significant fibrosis as Vibration controlled transient elastography (VCTE) liver stiffness measurements (LSM) value ≥7.9 kPa. We calculated the adjusted odds ratio (OR) and 95% confidential intervals (CI) for associations with NAFLD and significant NAFLD fibrosis using multivariable logistic regression.

RESULTS

Overall, among 4,024 individuals aged ≥20 years included in the analysis, 56.7% had NAFLD by CAP. In comparison, when defined by elevated liver enzymes, NAFLD prevalence was 12.4%. The prevalence of significant NAFLD fibrosis by VCTE LSM was 14.5%. NAFLD prevalence increased with age, was higher among men than women and among Hispanics compared with non-Hispanic whites. Individuals who were obese, had metabolic syndrome (MetS) and type 2 diabetes were more likely to have NAFLD compared to those that who were not obese or without MetS/diabetes. Inadequate physical activity (OR = 1.57, 95% CI: 1.18-2.08) was also a factor associated with NAFLD. MetS, high waist circumstance, diabetes and hypertension were independently associated with significant NAFLD fibrosis.

CONCLUSIONS

NAFLD and significant NAFLD fibrosis are highly prevalent in U.S. general population.