Age-related changes in stroke risk in men with hypertension and normal blood pressure

Background and Purpose Stroke is a major contributor to total morbidity and mortality in older individuals, and hypertension is an important risk factor for stroke. Relatively few data exist on whether this relationship changes with age. Methods To examine age-related changes in the relation ships between risk of stroke and hypertension, we examined the 6-year incidence of stroke among men aged 45 to 81 years using updated blood pressure data from three examinations of Japanese-American men from the Honolulu Heart Program. Results Both the prevalence of hypertension (systolic blood pressure greater than or equal to 160 mm Hg or diastolic blood pressure greater than or equal to 95 mm Hg or the use of antihypertensive medication) and the 6-year incidence of stroke increased significantly with increasing age (P<.01). The increase In thromboembolic stroke incidence with age was more marked in those who were normotensive at baseline (2.7/1000 in those aged 45 to 54 years to 23.9/1000 in those greater than or equal to 65 years; P<.001) than in hypertensive men (20.6/1000 in those aged 45 to 54 years to 33.5/1000 in those greater than or equal to 65 years; P<.01). The age-related increase in risk of thromboembolic stroke among normotensive men resulted in a decrease in the percentage of strokes attributable to hypertension (50% in those aged 45 to 54 years to 18% in those greater than or equal to 65 years; P<.05). Similar trends were seen for hemorrhagic stroke. There were no age-related changes in the relationships of other major atherosclerotic risk factors with stroke. The hypertension/stroke relationships were present after multivariate adjustment for age, smoking, cholesterol, and other factors. Conclusions In view of the greater prevalence of hypertension and the proven efficacy of treatment in the elderly, these findings do not negate the value of aggressive screening and treatment of hypertension in this age group. However, it appears that other unidentified factors have an increasing role in the causation of stroke with advancing age.