Isolated Systolic Hypertension and Risk of Stroke in Japanese-American Men

Background and Purpose This article examines prevalence of isolated systolic hypertension (ISH) in a population of Japanese-American men living in Hawaii and compares rates of stroke among those with ISH, isolated diastolic hypertension (IDH), combined systolic/diastolic hypertension (SDH), and nonhypertension. Methods Eight thousand six men aged 45 to 68 years participated in a baseline examination as part of a prospective study of coronary heart disease and stroke and were followed up for 20 years for incident disease and total mortality. Men were divided into four groups according to baseline blood pressure: ISH (systolic blood pressure [SBP] ≥160 mm Hg and diastolic blood pressure [DBP] <90 mm Hg); IDH (SBP <160 mm Hg and DBP ≥90 mm Hg); SDH (SBP ≥160 mm Hg and DBP ≥90 mm Hg); and nonhypertension (SBP <160 mm Hg and DBP <90 mm Hg). Results Men with ISH had the highest rates of stroke, followed by men with SDH. Men with IDH had rates only slightly higher than men in the nonhypertension group. Relative risk adjusted for other risk factors varied by age group. For men aged 45 to 54 years, relative risks of stroke associated with ISH, IDH, and SDH compared with nonhypertensive subjects were 4.8, 1.4, and 4.3, respectively. For men aged 55 to 68 years, the same relative risks were 1.2, 1.8, and 1.7. Excluding men on antihypertensive medication at baseline did not alter results. Conclusions ISH had a much greater impact on risk of stroke in younger than in older men. The results suggest that while ISH is more common in older men, in younger men it is associated with higher relative risk of stroke.