The association of weight gain with nonalcoholic fatty liver disease and fibrosis detected by FibroScan in the United States

BACKGROUND: Studies have reported the association between weight gain and nonalcoholic fatty liver disease (NAFLD) in the Asian population. We investigated the association between weight gain, NAFLD and significant fibrosis measured by transient elastography in a representative Unites States sample. METHODS: A cross-sectional study of 2849 participants was performed using the 2017-2018 National Health and Nutrition Examination Survey. We defined NAFLD by controlled attenuation parameter (CAP) scores and significant fibrosis (≥F2) by liver stiffness measurements using transient elastography, in the absence of other causes of chronic liver disease. A questionnaire that assessed weight change over 1 (short term) and 10 years (long term) was utilized. RESULTS: Age- and sex-adjusted odds ratios (OR) for NAFLD, comparing the third and fourth quartiles (weight-gain group) with the second quartile (weight-stable group, reference), were 1.61 (95% confidence interval [CI] 1.07-2.43) and 3.58 (95%CI 2.19-5.86), respectively. The association between weight gain and NAFLD remained significant after adjustment for demographic and metabolic risk factors (OR 1.87, 95%CI 1.19-2.95 for CAP score ≥263 dB/m; OR 2.23, 95%CI 1.48-3.35 for CAP ≥285 dB/m). In terms of significant fibrosis, multivariate-adjusted OR for significant fibrosis were 1.99 (95%CI 1.05-3.79 for the third quartile) and 3.12 (95%CI 1.46-6.65 for the fourth quartile), respectively. A statistically significant association between weight gain over 1 year and NAFLD was noted, whereas no such association was found between weight gain and significant fibrosis. CONCLUSION: Weight gain over 10 years was associated with increased odds of NAFLD and significant fibrosis.