Association Between Nonalcoholic Fatty Liver Disease and Future Deterioration of Metabolic Health: A Cohort Study

Objective: It was hypothesized that the presence of nonalcoholic fatty liver disease (NAFLD) at baseline predicts future conversion from the metabolically healthy (MH) to the metabolically unhealthy (MU) phenotype according to body fat mass. Methods: A total of 22,551 Korean participants (13,601 men and 8,950 women) aged 18 to 78 years in the Kangbuk Samsung Health Study cohort were enrolled from 2007 to 2013. Results: During a median of 5.1 years of follow-up (interquartile range 2.1-9.8 years), 23.5% (n = 5,298) of MH individuals converted to the MU phenotype. NAFLD at baseline predicted conversion independent of age, sex, BMI, lifestyle factors, individual components of metabolic syndrome, and insulin resistance (HR, 1.29; 95% CI: 1.19-1.39; P < 0.0001). In participants with lower BMI and fat mass, NAFLD was strongly associated with conversion; however, as BMI and fat mass increased, the risk decreased, and there was no association in participants with higher BMI and fat mass (P < 0.0001 for trend). Conclusions: NAFLD at baseline was independently associated with future conversion from the MH to the MU phenotype.