Body mass index and serum aminotransferase levels in Korean men and women

BACKGROUND AND AIMS: Obesity has been postulated as contributing to the risk of nonalcoholic steatohepatitis. With the surging obesity epidemic, an ensuing epidemic of nonalcoholic steatohepatitis and its sequelae is of concern. The objectives of this clinical research study were to examine the association between body mass index (BMI) and serum aminotransferase levels. METHOD: A study was carried out on 1,166,847 Koreans (731,560 men and 435,287 women), 30 to 95 years of age, who received health insurance from the National Health Insurance Corp and had a biennial medical evaluation from 1992 to 1995. RESULTS: Across the range of BMI values (<18.5 to 32 kg/m) in men, alanine aminotransferase (ALT) was estimated to increase by 18.8 U/L and aspartate aminotransferase (AST) increased by 7.1 U/L. In women, ALT increased by 9.9 U/L, whereas AST increased by 4.5 U/L. In men, interactions between BMI and alcohol consumption were significant (P<0.001) for ALT and AST, but the degree of effect modification was quantitatively minor. However, ALT and AST levels were somewhat higher in heavy alcohol drinkers than in nondrinkers. For women, the relationship of aminotransferase levels with BMI did not vary by alcohol consumption. The relationship of BMI with aminotransferase weakened with increasing age. CONCLUSIONS: In Korea, ALT and AST are strongly associated with BMI and increased progressively from the lowest to the highest strata of BMI. The association of BMI with aminotransferase levels was modified by age and sex.