Elevated alanine aminotransferase is associated with metabolic syndrome but not consistently associated with impaired fasting glucose or type 2 diabetes mellitus

Background: Abnormally elevated alanine aminotransferase (ALT) of nonspecific causes is a common outpatient problem. Without considering ethnicity, several studies had suggested that it was associated with insulin resistance (IR). Objective: To investigate whether nonspecific elevated ALT in Taiwanese population could reflect a likely underlying IR and was associated with impaired fasting glucose or type 2 diabetes mellitus (IFG/T2DM). Methods: The health examination profiles of 1313 Taiwanese were investigated cross-sectionally. The prevalence and odds ratios (ORs) for IFG/T2DM and metabolic abnormalities in relation to elevated ALT were analyzed. Results: Subjects with metabolic syndrome (MS) all had IFG/T2DM. The elevated ALT significantly correlated with MS and IFG/T2DM (i.e., 19.9-29.2% vs. 7.8% for MS, and 27.0-31.5% vs. 16.1% for IFG/T2DM). However, after excluding MS and adjustment for age and sex, the elevated ALT alone was not consistently associated with IFG/T2DM (36 < ALT ≤ 80 IU/L with OR 0.97, 95% CI 0.58-1.61; 80 < ALT ≤ 120 IU/L with OR 0.55, 95% CI 0.13-2.37; none with ALT > 120 had IFG). Conclusions: In a cross-sectional analysis of Taiwanese industrial employees, elevated ALT associated with MS, but in subjects who did not meet MS criteria, elevated ALT by itself did not associate with IFG/T2DM.