Plasma Hepatic Transaminases and Incidence of Metabolic Syndrome Before Midlife in Military Adults: A CHIEF Cohort Study.

Abstract

Background: Plasma AST and ALT may reflect the nonalcoholic fatty liver disease (NAFLD) severity and have been associated with the risk of MetS in middle- or old-aged individuals.

Aims: This study aimed to examine the associations of plasma hepatic aspartate and alanine transaminases (AST and ALT) levels with incident metabolic syndrome (MetS) in young adults, which have not been verified before.

Objective: The goal of this study was to identify the association between plasma hepatic transaminases and the incidence of new-onset MetS among young adults.

Methods: There were 2,804 military men and women, with ages of 18-39 years, free of baseline MetS and any viral hepatitis in Taiwan in 2014. Incident MetS were followed in the annual military health examinations from baseline till the end of 2020. The definition of MetS was made using the criteria of the International Diabetes Federation. Plasma concentrations of AST and ALT were checked at baseline. A Multivariable Cox regression model with adjustments for sex, age, each component of MetS, body mass index, substance use status, and physical activity at baseline was performed to determine the associations. Subgroup analyses were performed according to sex and each MetS component.

Results: During a median follow-up of 5.8 years, 644 incident MetS (23.0%) developed. ALT and AST levels (each 10 U/L increase) were respectively associated with 5% and 11% increased risk of incidence of MetS (hazard ratios (HRs) and 95% confidence intervals (CIs): 1.05 (1.01-1.09) and 1.11 (1.04-1.19), respectively). In subgroup analyses, the risk of incidence of MetS with ALT and AST levels respectively increased 75% and 114% in women (HRs: 1.75 (1.07-2.87) and 2.14 (1.35-3.41), respectively), and 7% and 14% in those free of central obesity (HRs: 1.07 (1.02-1.11) and 1.14 (1.06-1.23), respectively) which were higher than their counterparts (p-values for interaction by sex: 0.06 and 0.001, respectively; and by central obesity: 0.04 and 0.07, respectively).

Conclusion: Plasma hepatic transaminase levels were positively associated with incident MetS among young adults. The individual role of central obesity and sex on the association of ALT and AST with incident MetS should be further clarified.