The long-term effects of a cardiovascular disease prevention trial: The Stanford Five-City Project

Objectives. This study examined long-term effects of a health-education intervention trial to reduce the risk of cardiovascular disease. Methods. Surveys were conducted in California in two treatment and two control cities at baseline (1979/1980), after the 6-year intervention (1985/1986), and 3 years later at follow-up (1989/1990). Net treatment/control differences in risk-factor change were assessed for women and men 25 to 74 years of age. Results. Blood pressure improvements observed in all cities from baseline to the end of the intervention were maintained during the follow-up in treatment but not control cities. Cholesterol levels continued to decline in all cities during follow-up. Smoking rates leveled out or increased slightly in treatment cities and continued to decline in control cities but did not yield significant net differences. Both coronary heart disease and all-cause mortality risk scores were maintained or continued to improve in treatment cities while leveling out or rebounding in control cities. Conclusions. These findings suggest that community-based cardiovascular disease prevention trials can have sustained effects. However, the modest net differences in risk factors suggest the need for new designs and interventions that will accelerate positive risk-factor change.