Data from observational studies involving more than 1 million individuals have indicated that death from both IHD and stroke increases progressively and linearly from levels as low as 115 mmHg SBP and 75 mmHg DBP upward (figures 9 and 10).¹⁸ The increased risks are present in individuals ranging from 40 to 89 years of age. For every 20 mmHg systolic or 10 mmHg diastolic increase in BP, there is a doubling of mortality from both IHD and stroke.

Figure 9

Ischemic heart disease mortality rate in each decade of age versus usual blood pressure at the start of that decade IHD, ischemic heart disease

Figure 10

Stroke mortality rate in each decade of age versus usual blood pressure at the start of that decade Source: Reprinted with permission from Elsevier. Lewington S, et al. Age-specific relevance of usual blood pressure to vascular mortality: A meta-analysis (more...)

In addition, longitudinal data obtained from the Framingham Heart Study have indicated that BP values between 130–139/85–89 mmHg are associated with a more than twofold increase in relative risk from cardiovascular disease (CVD) as compared with those with BP levels below 120/80 mmHg (figure 11).¹⁹

Figure 11

Impact of high normal blood pressure on the risk of cardiovascular disease Cumulative incidence of cardiovascular events in women (panel A) and men (panel B) without hypertension, according to blood pressure category at the base-line examination. Vertical (more...)