Blood pressure changes as predictors of future mortality in the seven countries study.J Hum Hypertens. 1991 Jun; 5(3):137-44.JH
Twelve cohorts of men aged 40-59 at entry, enrolled in six countries (Finland, The Netherlands, Italy, Yugoslavia, Greece and Japan), giving a total of 8,287 subjects, were examined for the measurement of cardiovascular risk factors and then followed-up for 20 years. Changes of systolic blood pressure (SBP) occurred over the first 10 years in 6,767 men and these values, computed by an integral-like procedure (Delta-SBP), were used as possible predictors of fatal events recorded in the second 10 years of follow-up. Men who had a relative increase of SBP in the first 10 years showed an excess risk of death as compared with those who had a relative decrease of SBP, after adjustment for age and entry levels of SBP. Such relative risks were greater than 1 in the cohorts pooled within each of the six countries, ranging from 1.07 to 1.79 for all causes of death and from 1.12 to 2.15 for atherosclerotic cardiovascular disease deaths (coronary, stroke and peripheral atherosclerotic disease). The Cox model was solved using the same two end-points as dependent variables and, as coviariates, six risk factors measured at entry examination (age, cigarettes smoked per day, body mass index, serum cholesterol, physical activity at work and systolic blood pressure). By adding Delta-SBP the predictive power of the models was significantly improved and the coefficients of Delta-SBP proved to be statistically significant.