Stroke risk from alcohol consumption using different control groups

Abstract

Background and purpose: Our aim in this study was to investigate the relation between chronic alcohol consumption and stroke.

Methods: A case-control study was carried out using two hospital-based control groups and the results of a community-based survey of alcohol consumption. Hospital-based control subjects were chosen either from "general" medical admissions or a subset of "select" admissions that excluded possible alcohol-related admissions. Cases were selected from hospital inpatients.

Results: The relative risk for stroke associated with alcohol consumption greater than 300 grams per week for general control subjects was 0.73 (95% confidence interval [CI], 0.54-3.49) compared with 1.30 (95% CI, 0.42-4.05) for select control subjects. The odds ratio was further increased to 1.93 (95% CI, 0.87-4.28) using data from the community-based survey. None of these estimates were statistically significant.

Conclusions: These results illustrate how the risk associated with alcohol consumption varies depending on the choice of control groups and may explain the contradictory results from previous case-control studies. Because of different biases associated with control selection, we believe that the results of this study are consistent with those of other studies that demonstrate a modest increased risk for stroke associated with alcohol consumption.