Liver Enzymes, the Metabolic Syndrome, and Incident Diabetes The Mexico City Diabetes Study

OBJECTIVE — To test the hypothesis that enzymes conventionally associated with liver dysfunction (aspartate aminotransferase, alanine aminotransferase, -glutamyltransferase [GGT], and alkaline phosphatase) may predict diabetes. RESEARCH DESIGN AND METHODS — From a population-based diabetes survey, we selected 1,441 men and women in whom serum enzyme levels were 3 SDs of the mean population value, alcohol intake was 250 g/week, and hepatitis B and C virus testing was negative. At follow-up (7 years), 94 subjects developed diabetes and 93 impaired glucose toler-ance (IGT). RESULTS — At baseline, all four enzymes were related to most of the features of the metabolic syndrome. After controlling for sex, age, adiposity/fat distribution, alcohol intake, serum lipids, and blood pressure, higher alanine aminotransferase and GGT values were significantly (P 0.01) associated with both IGT and diabetes, whereas alkaline phosphatase was associated with diabetes only (P 0.0004) and aspartate aminotransferase with IGT only (P 0.0001). Raised GGT alone was associated with all the features of the metabolic syndrome. Raised GGT was a significant predictor of either IGT or diabetes (odds ratio 1.62 [95 % CI 1.08–2.42] top quartil