Secular decrease in blood pressure and reduction in mortality from cardiovascular disease in Israeli workers

The reasons for the dramatic reduction in age-adjusted mortality from cardiovascular disease (CVD) since the 1970s in developed countries remain uncertain. In the following study we compare the cardiovascular and all-cause mortality rates over an 11-year period in two well-defined employed male cohorts aged 40 - 69 years old recruited 24 years apart. Blood pressure and other risk markers for CVD were assessed at the time of inception ( 1963 for 10 048 male civil servants and 1985 - 1987 for 2237 male industrial workers). Compared to the 1987 cohort, the 1963 cohort show an increase of 8.7 mmHg in the mean systolic blood pressure (SBP) (95% confidence interval (CI): 7.7, 9.6) and a concomitant hazard ratio for CVD mortality of 1.47 (95% CI: 1.16, 1.87). After adding SBP to the analysis, the hazard ratio for CVD mortality in the 1963 cohort decreased to 1.18 ( 95% CI: 0.88, 1.43). Adding the other risk modifiers to the analysis did not modify the hazard ratio to the same extent. Similar results were obtained for all-cause mortality. We conclude that declining blood pressure values are a major factor in explaining the secular decrease in CVD mortality over a period of 24 years in Israel.