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.