Gamma-glutamyltransferase, alcohol, and blood pressure. A four year follow-up study

PURPOSE: We performed this study to see: 1) whether gamma-glutamyltransferase (GGT) was a predictor for hypertension irrespective of amount of alcohol consumption; and 2) whether the relationship between alcohol consumption and blood pressure (BP) was different depending on GGT. METHODS: This study included 8170 healthy male workers in a steel manufacturing company who had undergone health examinations in both 1994 and 1998. RESULTS: The adjusted relative risk (RR) for hypertension over four years among those with GGT >or=30 U/L at baseline was 1.6 (95% confidence interval (CI): 1.1-2.4), compared to those with GGT < 30 U/L. This relationship was shown only in drinkers. Among subjects with GGT < 30U/L, no matter how much the subjects drank, the risk of hypertension in drinkers was similar with that of non-drinkers. However, among those with GGT >or=30 U/L, adjusted RRs for light, moderate, and heavy drinkers compared to non-drinkers were 1.4 (95% CI: 0.5-4.5), 5.2 (95% CI: 1.5-18.0), and 5.3 (95% CI: 1.0-27.6). CONCLUSIONS: This study showed that elevated GGT could be a predictor for hypertension in drinkers and the relationship between alcohol consumption and hypertension was shown only among those with GGT >or= 30 U/L at baseline. These findings suggest that increased serum GGT levels may reflect individual susceptibility to the blood pressure raising effect of alcohol.