Impact of systolic and diastolic blood pressure on ischemic vascular diseases in French-Canadian men from 1974 to 1990.

The relationships of systolic and diastolic blood pressure (BP) to ischemic heart disease (IHD), intermittent claudication (IC) and stroke were evaluated in 4385 men (aged 35 to 64 years in 1973) clinically free from these vascular diseases at entry and followed for 16 years. The mean of two readings measured in 1973-74 was used as the baseline BP. The cut-of for quintile 5 was systolic BP greater than 152 mmHg and diastolic BP greater than 92 mmHg. Relative risks (RR) were adjusted for main risk factors and calculated separately for systolic and diastolic BP. From 1974-90, 1120 first ischemic vascular events were documented: 792 IHD, 216 IC and 112 strokes. The incidences of each ischemic vascular disease increased, starting at quintile 4, for either systolic or diastolic BP. For systolic BP, the adjusted RR of quintile 5 compared with quintile 1 were 1.8 for IHD (95% confidence interval 1.4 to 2.2), 2.7 for IC (1.8 to 4.2) and 3.8 for stroke (2.1 to 7.0); for diastolic BP, the RR were 1.8 for IHD (1.5 to 2.3), 1.5 for IC (1.0 to 2.1) and 3.5 for stroke (2.0 to 6.4). For IHD, the RR of BP were similar for angina and myocardial infarction, and more pronounced for coronary death. In this population, elevated BP constitutes an important risk factor not only for stroke, but also for the main manifestations of IHD and IC. The impact of systolic BP was at least as significant as that of diastolic BP on these ischemic vascular events.