Elevated alpha-fetoprotein in asymptomatic adults: Clinical features, outcome, and association with body composition

BACKGROUND AND AIM: Apparently healthy individuals with elevated serum alpha-fetoprotein (AFP) levels (>7 ng/mL) for unknown causes visit clinics. We investigated their clinical characteristics, outcomes, and relationship with body fat deposition and muscle mass. METHODS: The case group included asymptomatic 137 individuals with “elevated AFP level” (R772) diagnostic code from 2009 to 2018 in a tertiary hospital. The control group enrolled 274 age- and sex-matched patients with <5 cm hepatic hemangiomas. Hepatic, visceral, and psoas muscle adiposity and psoas muscle index (PMI) were measured in the subgroups of 45 cases and 90 controls with pre-contrast computed tomography (CT) images. RESULTS: The case group (mean age 47.5 years, male 35.8%) showed higher AFP levels (10.3 vs 2.5 ng/mL, p<0.001) and total bilirubin (0.8 vs 0.7 mg/dL, p<0.001), but a lower body mass index (22.2 vs 23.3 kg/m(2), p = 0.011) and alanine aminotransferase levels (17.0 vs 19.0 IU/L, p = 0.047) than the controls. During 13 months of median follow-up, there was no cancer or liver disease development. The AFP levels were stable. In the subgroups with CT images, cases showed a lower proportion of hepatic steatosis (4.4% vs 18.9%, p = 0.023), higher psoas muscle attenuation (48.2 vs 43.8 Hounsfield units, p<0.001) and higher PMI (5.7 vs 4.2 cm(2)/m(2), p<0.001) than the controls. CONCLUSION: Elevated AFP levels in asymptomatic individuals may play a role in expressing a protective phenotype against hepatic steatosis, myosteatosis, and sarcopenia. AFP levels in patients with elevated AFP were stable during follow-up without liver injury or cancer development. Interaction between AFP expression and steatosis warrants further study.