Independent and opposite associations of trunk fat and leg fat with liver enzyme levels.

BACKGROUND: In contrast to trunk fat mass (TFM), which is associated with cardiovascular risk markers, leg fat mass (LFM) displays independent protective effects against atherosclerosis. Little is known about the respective influence of central and peripheral adiposity on liver enzyme levels. AIMS: To assess the respective influence of TFM and LFM on alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT) levels, and to test whether LFM might protect against an increase of liver enzyme levels.
METHODS: Cross-sectional study on 1442 patients (women: 1155; men: 287) referred for overweight/obesity over 3 years. Body composition was analysed by dual-energy X-ray absorptiometry. The relationships among liver enzymes, age, weight, height, body mass index (BMI), biological indices and body composition were studied.
RESULTS: The mean BMI was 39.7 +/- 7.9 kg/m(2) in women and 38.2 +/- 6.6 kg/m(2) in men. In women, after adjustement for confounding factors, ALT, AST and GGT were negatively and independently correlated with LFM and positively with TFM. Similar independent associations were observed for ALT and AST in men. The strongest associations were found for ALT in both women and men.
CONCLUSIONS: As observed for cardiovascular risk factors, LFM and TFM are inversely and independently correlated with liver enzyme levels in obese patients. LFM may confer independent protective effects against obesity-associated liver damage.