ALT levels linked to metabolic syndrome

Australian researchers have discovered a strong association between serum alanine aminotransferase (ALT) concentrations and the metabolic syndrome (Met S) that cannot be explained by insulin resistance. Writing in the American Journal of Gastroenterology the researchers from Western Australia also found that elevated ALT levels were not an independent risk factor for cardiovascular morbidity. Nonalcoholic fatty liver disease (NAFLD) has recently emerged as a disorder that is strongly associated with Met S. It varies in its clinical manifestation and occurs in 9% of overweight individuals and 21-33% of those with morbid obesity. It is also the most common cause of increased ALT in developed countries, the authors wrote. To determine whether elevated ALT concentrations were predictive of Met S or cardiovascular events the researchers studied 3,719 subjects participating in the Busselton population health survey who did not have serologically diagnosable chronic liver disease or excessive consumption of alcohol. The prevalence of Met S was 17% in men and 15% in women, with hypertension being the most common component. ALT was significantly associated with Met S and this association remained significant after adjusting for insulin resistance. The researchers found no positive association between ALT and incident CVD events over the 10 year follow-up period. However, they noted that their study did not allow for an assessment of whether subjects who have CVD events and Met S have a greater propensity to develop liver disease. “Insulin resistance has been proposed to be the underlying factor linking obesity to NAFLD… we show that factors other than insulin resistance may be important in mediating the interaction between liver disease and Met S,” the authors said. “Further characterization of such factors will be important in defining potential new interventions in NAFLD,” they concluded. Am J Gastronenterology 2009; published online before print....