DETERMINANTS OF GAMMA-GLUTAMYL-TRANSFERASE - POSITIVE INTERACTION WITH ALCOHOL AND BODY-MASS INDEX, NEGATIVE ASSOCIATION WITH COFFEE

gamma-Glutamyltransferase is widely used as a marker of alcohol intake although its performance is poor. This might be related to other cond itions influencing gamma-glutamyltransferase activity. The authors stu died determinants of gamma-glutamyltransferase activity in a random sa mple (n = 6,010) drawn from the general population aged 25-64 years in Finland in 1992. In regression analysis, coffee intake and drinking b oiled coffee were significantly (p < 0.01) negatively related to gamma -glutamyltransferase, whereas age, male gender, the number of cigarett es per day, serum total cholesterol and high density lipoprotein chole sterol, heart rate, and diastolic blood pressure were significantly po sitively related to gamma-glutamyltransferase. A significant (p = 0.02 ) positive interaction was observed between alcohol intake and body ma ss index, In logistic regression analysis, the proportion of elevated gamma-glutamyltransferase values (greater than or equal to 50 U/liter) was significantly decreased, compared with lifelong abstainers, at th e alcohol intake level of <40 g/week (odds ratio (OR) = 0.51, 95% conf idence interval (CI) 0.29-0.92) and significantly increased at the lev el of greater than or equal to 300 g/week (OR = 2.81, 95% CI 1.35-5.85 ) among nonobese subjects (body mass index <27 kg/m(2)). Among obese s ubjects, the respective proportion was significantly increased at the alcohol intake level of greater than or equal to 40 g/week (OR = 2.02, 95% CI 1.11-3.68), The proportion of elevated gamma-glutamyltransfera se values was significantly decreased at the coffee intake levels of b oth four to six cups a day (OR = 0.44, 95% CI 0.31-0.62) and seven or more cups a day (OR = 0.36, 95% CI 0.24-0.53). In addition, drinkers o f boiled coffee had elevated gamma-glutamyltransferase values more oft en than drinkers of filtered or instant coffee (OR = 0.59, 95% CI 0.42 -0.84). No effects of alcoholic beverage preference were observed. Ele vated gamma-glutamyltransferase activities appear to be related to hea vy alcohol intake among the nonobese and to very light intake among ob ese subjects. Coffee appears to decrease gamma-glutamyltransferase act ivity.