The relationships of gender, cigarette smoking, and hypertension with the risk of aneurysmal subarachnoid hemorrhage: a case-control study in Nagoya, Japan.

Purpose: To examine the relationship of gender, cigarette smoking, and a history of hypertension to the risk of aneurysmal subarachnoid hemorrhage (SAH), using a case-control study.

Methods: Case subjects consisted of a consecutive series of 201 patients with spontaneous SAH with aneurysm(s) confirmed by angiography and/or CT scan. One hospital and one community control subject was matched to each case by gender and age (+/- 2 years). Multiple conditional logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) adjusted for potential confounders.

Results: Current smoking and a history of hypertension were each significantly associated with an increased risk of subarachnoid hemorrhage for men and women combined. There was also a non-significant trend towards synergism between these two factors with respect to an increased risk of subarachnoid hemorrhage for each gender separately and both combined. A significantly increased risk was observed for a history of hypertension (adjusted OR, 3.5; 95% CI, 1.2-14.7) among men, for current smoking alone (adjusted OR, 2.9; 95% CI, 1.1-7.7), and a history of hypertension alone (adjusted OR, 2.6; 95% CI, 1.4-5.1) among women.

Conclusions: Trends towards gender differences and synergism emerged in the relationship of cigarette smoking and a history of hypertension of the risk of SAH provides useful information for targeting individuals/populations in programs for the primary prevention of SAH by gender.