Modifiable clinical and lifestyle factors are associated with elevated alanine aminotransferase levels in newly diagnosed type 2 diabetes patients: results from the nationwide DD2 study.

Background: Current literature lacks data on markers of non-alcoholic fatty liver disease (NAFLD) in newly diagnosed type 2 diabetes mellitus (T2DM) patients. We therefore, conducted a cross-sectional study to examine modifiable clinical and lifestyle factors associated with elevated alanine aminotransferase (ALT) levels as a marker of NAFLD in new T2DM patients.

Methods: Alanine aminotransferase levels were measured in 1026 incident T2DM patients enrolled in the nationwide Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort. We examined prevalence of elevated ALT (>38 IU/L for women and >50 IU/L for men) and calculated prevalence ratios associated with clinical and lifestyle factors using Poisson regression. We examined the association with other biomarkers by linear regression.

Results: The median value of ALT was 24 IU/L (interquartile range: 18-32 IU/L) in women and 30 IU/L (interquartile range: 22-41 IU/L) in men. Elevated ALT was found in 16% of incident T2DM patients. The risk of elevated ALT was increased in patients who were <40 years old at diabetes debut [adjusted prevalence ratio (aPR): 1.96, 95% confidence interval (CI): 1.15-3.33], in those with alcohol overuse (>14/>21 drinks per week for women/men) (aPR: 1.60, 95% CI: 1.03-2.50), and in those with no regular physical activity (aPR: 1.42, 95% CI: 1.04-1.93). Obesity and metabolic syndrome per se showed no association with elevated ALT when adjusted for other markers, whereas we found positive associations of ALT with increased C-peptide (β = 0.14, 95% CI: 0.06-0.21) and fasting blood glucose (β = 0.07, 95% CI: 0.03-0.11).

Conclusions: Among newly diagnosed T2DM patients, several modifiable clinical and lifestyle factors are independent markers of elevated ALT levels.