Background: The elevation of liver enzymes, in the absence of viral hepatitis or heavy alcohol consumption, has been related to nonalcoholic fatty liver disease [NAFLD], which is associated with insulin resistance and metabolic syndrome.
Objective: To examine the association between liver enzymes and metabolic risk factors, including diabetes mellitus [DM]
and dyslipidemia, in Thai adults.
Materials and Methods: A total of 4,317 adults were recruited from a health check-up clinic at Srinagarind Hospital, a tertiary care setting. After excluding previous history of all metabolic risk factors, liver disorder, vital hepatitis, and moderate to heavy alcohol drinking, body weight [BW], blood pressure [BP], fasting plasma glucose [FPG], total cholesterol [TC], triglyceride [TG], alanine aminotransferase [ALT], and aspartate aminotransferase [AST] were measured. The liver enzyme levels were categorized into quartiles and their associations with FPG, TC, TG, and prevalence of metabolic risk factors (including DM and dyslipidemia) were tested using multinomial logistic regression. Logistic regression was performed to calculate the odds ratio [OR] and 95% confidence interval [95% CI] of the relationship between liver enzymes and prevalence of each metabolic risk factor.
Results: Prevalence rates of elevated ALT and AST levels, defined as being more than twice of upper normal limit [UNL], in the entire cohort were 5.3 and 2.8%, respectively. After categorizing ALT and AST into quartiles, we found that the
prevalence of DM, IFG, and hypertriglyceridemia were higher in the higher ALT and AST quartiles, but the magnitude of
association was higher in ALT. After adjusting for age and BMI, every twofold elevation in ALT and AST was found to be
associated with an increased risk for DM (OR 1.42, 95% CI: 1.23 to 1.63 vs. 1.35, 95% CI: 1.17 to 1.57), IFG (OR 1.49, 95% CI: 1.31 to 1.69 vs. 1.40, 95% CI: 1.22 to 1.62) and hypertriglyceridemia (OR 1.42, 95% CI: 1.29 to 1.56 vs. 1.22, 95% CI: 1.09 to 1.36), respectively). However, the elevations of ALT and AST were not associated with increased risk of hypertension or hypercholesterolemia in the present study.
Conclusion: Elevations in ALT and AST levels independently predict DM, IFG, and hypertriglyceridemia in Thai adults.

Keywords: Diabetes, Liver enzyme, Metabolic syndrome