title: Serum γ-glutamyltransferase: independent predictor of risk of diabetes, hypertension, metabolic syndrome, and coronary disease.
abstract: Serum γ-glutamyltransferase (GGT) is associated with oxidative stress and hepatic steatosis. The extent to which its value in determining incident cardiometabolic risk (coronary heart disease (CHD), metabolic syndrome (MetS), hypertension and type 2 diabetes) is independent of obesity needs to be further explored in ethnicities. After appropriate exclusions, a cohort of 1,667 adults of a general population (age 52 ±11 years) was evaluated prospectively at 4 year's follow-up using partly Cox proportional hazard regressions. GGT activity was measured kinetically, and values were log-transformed for analyses. MetS was identified by Adult Treatment Panel-III criteria modified for male abdominal obesity. Median (interquartile range) GGT activity was 24.9 (17.0; 35.05) U/l in men, 17.0 (12.3; 24.0) U/l in women. In linear regression analysis, while smoking status was not associated, (male) sex, sex-dependent age, alcohol usage, BMI, fasting triglycerides and C-reactive protein (CRP) were significant independent determinants of circulating GGT. Each 1-s.d. increment in (= 0.53 ln GGT) GGT activity significantly predicted in each sex incident hypertension (hazard ratio (HR) 1.20 (95% confidence interval (CI) 1.10; 1.31)), and similarly MetS, after adjustment for age, alcohol usage, smoking status, BMI and menopause. Strongest independent association existed with diabetes (HR 1.3 (95% CI 1.1; 1.5)) whereas GGT activity tended to marginally predict CHD independent of total bilirubin but not of BMI. Higher serum total bilirubin levels were protective against CHD risk in women. We conclude that elevated serum GGT confers, additively to BMI, risk of hypertension, MetS, and type 2 diabetes but only mediates adiposity against CHD risk.
authors.affiliation: Department of Cardiology, Cerrahpaşa Medical Faculty, Istanbul University, Istanbul, Turkey. alt_onat@yahoo.com.tr
authors.forename: Altan
authors.initials: A
authors.lastname: Onat
authors.forename: Günay
authors.initials: G
authors.lastname: Can
authors.forename: Ender
authors.initials: E
authors.lastname: Örnek
authors.forename: Gökhan
authors.initials: G
authors.lastname: Çiçek
authors.forename: Erkan
authors.initials: E
authors.lastname: Ayhan
authors.forename: Yüksel
authors.initials: Y
authors.lastname: Doğan
mesh_terms: D015331:Cohort Studies; D003327:Coronary Disease / Q000097:blood* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D007328:Insulin / Q000097:blood; D016014:Linear Models; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000503:physiopathology; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000503:physiopathology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D007328:Insulin; D014280:Triglycerides; D005723:gamma-Glutamyltransferase