Background and purpose: First-degree relatives of patients with subarachnoid hemorrhage (SAH) have a three to seven times greater risk of SAH than second-degree relatives and than the general population. If hypertension, which is in part genetically determined, contributes to this increased risk, the frequency of hypertension and its sequelae would be expected to be higher in first- than in second-degree relatives of patients with SAH.
Methods: We compared the reported frequency of hypertension, stroke, and coronary heart disease between 1290 first- and 3588 second-degree relatives of a prospective series of patients with SAH.
Results: The relative risk adjusted for age and survival status in first-degree relatives was 2.3 (95% confidence interval [CI], 1.9 to 2.9) for hypertension, 1.8 (95% CI, 1.3 to 2.4) for stroke, and 1.9 (95% CI, 1.5 to 2.3) for coronary heart disease.
Conclusions: Hypertension is a familial factor contributing to the risk of SAH. Hypertension should be sought and treated in first-degree relatives of patients with SAH to reduce the increased risk of cerebrovascular and cardiovascular diseases.