Serum gamma-glutamyl transferase, self-reported alcohol drinking, and the risk of stroke

Background and Purpose-There is still conflicting evidence regarding a link between alcohol drinking and the risk of stroke. In most prospective studies, the assessment of the alcohol drinking has been based on self-reporting, which may be unreliable. The aim of the present study was to examine the relationship between stroke and both the self-reported alcohol drinking and the serum gamma-glutamyl transferase (GGT) concentration, which was regarded as a biological marker of alcohol drinking. Methods-A prospective cohort study of 14 874 Finnish men and women aged 25 to 64 years who participated in a cardiovascular risk-factor survey in 1982 or 1987. The following risk factors, determined at baseline, were included in data analyses: self-reported alcohol drinking, GGT, smoking, blood pressure, serum cholesterol, and body mass index. The cohorts were followed until the end of 1994. Stroke events were identified through the national death registry and hospital discharge registry by computerized record linkage. Results-Serum GGT concentration was associated with the risk of total and ischemic stroke in both genders. There was also a significant association among men between GGT and the risk of intracerebral hemorrhage and among women between GGT and the risk of subarachnoid hemorrhage. The relationships remained statistically significant also after adjustment for other risk factors. Self-reported alcohol drinking did not associate with any type of stroke. Conclusions-These results support the hypothesis that excessive alcohol drinking is related to an increased risk of stroke. Biological markers of alcohol drinking, such as serum GGT level, are useful for the assessment of risks related to alcohol drinking.