The prevalence of elevated alanine transaminase and its possible causes in the general Korean population

The goal of the study was to investigate the current prevalence and causes of elevated alanine transaminase (ALT) in the general Korean population.

Incidentally elevated ALT is frequently found because of increasing access to hospitals and blood tests.

A population-based cross-sectional study was carried out based on the Fourth Korean National Health and Nutrition Examination Survey (K-NHANES). Eligible subjects included 7894 men and 10,197 women. We defined elevated ALT as >43 U/L. Among the subjects with elevated ALT, those who consumed alcohol, had the hepatitis B surface antigen (HBsAg), were obese (body mass index ≥25 kg/m), were insulin resistant (the homeostasis model assessment-insulin resistance), or had metabolic syndrome (MetS) were investigated.

The prevalence of elevated ALT was 7.4% in the Korean population. Increased ALT was more common in men (11.6%) than in women (3.1%) (P<0.001). Subjects with hypertension, diabetes, dyslipidemia (cholesterol ≥240 mg/dL or triglycerides ≥150 mg/dL), obesity, significant consumption of alcohol, HBsAg positive, or MetS were associated with elevated ALT (all P<0.001). The most common potential cause of elevated ALT was metabolic disorder (MetS, obesity, and/or insulin resistance), which comprised 74.9% of cases. MetS was found in 42.7% of men and 49.7% of women (P=0.031). Excess alcohol drinking was found in 29.6% of men and 7.5% of women with elevated ALT (P<0.001). HBsAg positivity was found in only 6% of subjects.

Incidentally elevated ALT is common in the Korean population. It is associated with metabolic disorders (obesity, insulin resistance, or MetS) in the majority of patients. This finding suggests that nonalcoholic fatty liver disease might be the most common cause of elevated ALT in the general Korean population.