Prevalence of Liver Steatosis and Fibrosis Detected by Transient Elastography in Adolescents in the 2017–2018 National Health and Nutrition Examination Survey

Background & aims: Metabolic-associated fatty liver disease (MAFLD) is common among adolescents, but the prevalence of significant fibrosis in this age group is not known. We aimed to estimate the prevalence of MAFLD and significant (≥F2) fibrosis by transient elastography (TE) in adolescents in the United States. Methods: We analyzed TE data from participants 12-18 years old included in the National Health and Nutrition Examination Survey 2017-2018 (data available from 867 adolescents). Steatosis was evaluated by the median controlled attenuation parameter (CAP) and fibrosis by median liver stiffness measurement. Results: Two-hundred forty participants (24.16%; 95% CI, 21.07-27.24) had any degree of steatosis (CAP≥248 dBm), 123 participants (11.6%; 95% CI, 9.19-14.06) had S3 steatosis (CAP≥280 dBm), and 51 participants (4.4%; 95% CI, 2.51-6.33) had significant fibrosis (liver stiffness ≥7.4 kPa). Multivariate analyses revealed that body mass index (odds ratio [OR] per unit increase, 1.2; 95% CI, 1.2-1.4), sex (OR female vs male participants , 0.5; 95% CI, 0.4-0.7), ethnicity (OR, Hispanic vs non-Hispanic white, 4.5; 95% CI, 1.7-11.8), and hypertension (OR, 3.5; 95% CI, 1.3-9.9) were associated with S3 steatosis, whereas body mass index (OR, 1.1 per unit increase; 95% CI, 1.0-1.2) and ethnicity (OR, non-Hispanic black vs non-Hispanic white, 3.9; 95% CI, 1.2-13.2) were associated with significant fibrosis. High proportions of participants with fibrosis were in the normal weight category (35%) and had normal levels of alanine aminotransferase (78%). Conclusions: Prevalence of MAFLD and significant fibrosis are alarmingly high in adolescents in the National Health and Nutrition Examination Survey 2017-2018. Levels of alanine aminotransferase and blood biomarkers do not correctly identify adolescents with more advanced disease. Effective noninvasive strategies to differentiate simple steatosis from progressive forms are urgently needed.