Significance of ALT/AST ratio for specifying subjects with metabolic syndrome in its silent stage

Aims: Association between metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD) was verified and significance of liver function tests, especially alanine aminotransferase/aspartate aminotransferase ratio (ALT/AST) to evaluate the statuses of MetS and/or visceral fat accumulation was examined. Materials and Methods: After excluding subjects with liver diseases other than NAFLD, 1643 male and 1764 female Japanese were cross-sectionally examined. The diagnosis of MetS was done by its clinical criteria for Japanese with some modifications. Results: Levels of AST, ALT, gamma glutamyl transpeptidase and ALT/AST were significantly higher in subjects with MS than in those without it. Stepwise regression analyses indicated that AST, ALT, and ALT/AST in male and ALT/AST in female were significantly associated with waist circumference (WC), a marker of visceral fat accumulation. Among these associations, the association between WC and ALT/AST was always significant even when subjects with normal level of ALT of WC were selectively examined. Conclusions: NAFLD can be considered as one of morbid conditions of MetS, i.e. visceral fat accumulation. Among liver function test items, ALT/AST could be a powerful index reflecting their progression even in their pre-diagnosis/silent phases.