Seven-year follow-up of cardiovascular study and maximal exercise of Chinese men

A seven-year follow-up in 1973 of a prospective cardiovascular study of 1820 initially, healthy, middle-aged Chinese men of 40-59 years of age identified 1745 (95.9%) known survivors, 49 (2.7%) interim deaths, and 26 (1.4) who could not be traced. Of the survivors, 1462 (83.8%) were re-examined, 292 (16.7%) had another treadmill test of maximal exercise, and 283 (16.2%) failed to return for re-examination. On the basis of interim surveillance of hospital admissions, questionnaires and re-examination, a greater incidence of noncardiovascular events (338 or 18.6%) than evidence of cardiovascular disease (220 or 12.1%) was found while the majority (1021 or 56.1%) remained healthy. Total mortality was 0.29 for men under 50 and 0.76 per 100 person-years for men of 50 or more years of age. Only nine, or 18.4% of the deaths were due to cardiovascular causes, and unexpectedly for this population sample, only three were attributed to stroke. When cardiovascular morbidity was related to presence of ST depression after maximal exercise, to hypertension at rest by WHO criteria, to both findings, or to absence of either on initial intake examination, incidence increased from 2.3% for NEITHER group, to 5.7% for ST group, to 11.9% for HT group, and to 25.0% for BOTH groups. Re-examination revealed more evidence of cardiovascular disease than did surveillance of hospital admissions. Additional to effects of aging and mild adiposity, longitudinal changes in blood pressure and ST depression, increasing in the NEITHER group, but less frequent in the other groups, showed some evidence of regression toward the mean, as well as emerging disease and the confounding effects of uncontrolled treatment of hypertension in many. The potential for prediction of subsequent cardiovascular morbidity or mortality appeared stronger for hypertension than for postexertional ST depression, although the two were additive in this population, which is more prone to hypertension and stroke but now is developing clinical manifestations of coronary heart disease more frequently.