Fat accumulation is the strongest contributor for nonalcoholic fatty liver disease (NAFLD)/ metabolic dysfunction-associated fatty liver disease (MAFLD) in male young adults even among nonobese (body mass index <25 kg/m 2 ) individuals.Sarcopenia and serum triglyceride levels may also play an important role in the pathogenesis of NAFLD/MAFLD among nonobese individuals.

We aimed to assess metabolic dysfunction-associated fatty liver disease (MAFLD) and alcohol-related liver disease (ALD) prevalence in young male adults and the role of health checkups in disease screening. We recruited 313 male graduate students at Gifu University in April 2022. With hepatic steatosis diagnosed by ultrasonography, MAFLD and nonalcoholic fatty liver disease (NAFLD) were diagnosed based on health checkup data, and ALD was diagnosed with alcohol consumption > 30 g/day. The ability of each variable to identify MAFLD, NAFLD, and ALD was assessed using logistic regression and receiver-operating characteristic curve analyses. Participants’ mean age was 23 (± 4) years, and MAFLD, NAFLD, and ALD prevalence was 11%, 17%, and 1%, respectively. Among Japanese male young adults, alanine aminotransferase (ALT) (odds ratio [OR] 1.04; 95% confidence interval [CI] 1.01–1.07; P = 0.008) and body mass index (BMI) (OR 2.02; 95% CI 1.58–2.58; P < 0.001) were independently associated with MAFLD. Furthermore, only the alcohol use disorders identification test (AUDIT) was able to identify ALD (OR 1.49; 95% CI, 1.28–1.74; P = 0.001). Our study revealed that health checkups, including measurement of ALT, BMI, and AUDIT, are important for screening MAFLD and ALD in younger generations.