Background: Elevated blood pressure is known to be a risk factor for death from coronary heart disease (CHD). However, it is unclear whether the risk of death from CHD in relation to blood pressure varies among populations.
Methods: In six populations in different parts of the world, we examined systolic and diastolic blood pressures and hypertension in relation to long-term mortality from CHD, both with and without adjustment for variability in blood pressure within individual subjects. Blood pressure was measured at base-line in 12,031 men (age range, 40 to 59 years) who were free of CHD. During 25 years of follow-up, 1291 men died from CHD.
Results: At systolic and diastolic blood pressures of about 140 and 85 mm Hg, respectively, 25-year rates of mortality from CHD (standardized for age) varied by a factor of more than three among the populations. Rates in the United States and northern Europe were high (approximately 70 deaths per 10,000 person-years), but rates in Japan and Mediterranean southern Europe were low (approximately 20 deaths per 10,000 person-years). However, the relative increase in 25-year mortality from CHD for a given increase in blood pressure was similar among the populations. The overall unadjusted relative risk of death due to CHD was 1.17 (95 percent confidence interval, 1.14 to 1.20) per 10 mm Hg increase in systolic pressure and 1.13 (95 percent confidence interval, 1.10 to 1.15) per 5 mm Hg increase in diastolic pressure, and it was 1.28 for each of these increments after adjustment for within-subject variability in blood pressure.
Conclusions: Among the six populations we studied, the relative increase in long-term mortality due to CHD for a given increase in blood pressure is similar, whereas the absolute risk at the same level of blood pressure varies substantially. If the absolute risk of CHD is used as an indication for antihypertensive therapy, these findings will have major implications for treatment in different parts of the world.