Stanford Community Trials

Background/Question:

Stanford, California and the surrounding area was chosen as one of three sites to conduct community surveys on cardiovascular disease (CVD). Two studies took place as part of the Stanford Community Trials: the Stanford Three-Community Study and the Stanford Five-City Project. The Three-Community Study measured the effectiveness of media campaigns and community-wide health education plus a specific high risk intervention on cardiovascular risk factor levels. The Five-City Project aimed a broad mediated and community-action campaign at risk factor reduction, decline in heart disease endpoints and cost-effectiveness measures.

Methods:

The Stanford Three-Community Study started in 1972 in the communities of Tracy, Gilroy and Watsonville, California. A random sample of adults aged 35-59 years was examined annually in each community with estimations of daily intake of nutrients, rate of smoking, knowledge of heart-disease risk factors, and laboratory and physical measurements of cholesterol, plasma renin, urinary sodium, blood pressure and weight. [1] A risk score was calculated for each participant using multiple logistic function of risk. [1] Mass media campaigns using television, radio, newspapers and posted advertisements were launched in Gilroy and Watsonville, while Tracy functioned as a control community. The intent of the campaigns was to “produce awareness of the probable causes of coronary disease and of the specific measures which may reduce risk and to provide the knowledge and skills necessary to accomplish and maintain recommended behavior changes.” [1] Those who were found at high risk in Watsonville were also given one-on-one counseling and education on heart disease.

The Stanford Five-City Project began in 1978 as a 13-year study. [2] The five northern California cities involved in the project were chosen for diversity of media outlets, population over 30,000 people, and socioeconomic and ethnic similarity. [3] Random selection of households was completed using city directories, and all persons aged 12-74 in each household were eligible to participate. Each community contributed 625 subjects. [3] Behavioral measures were taken with medical history and dietary questionnaires. Physiologic measurements included height, weight, plasma and urine samples, blood pressure and a fitness test using a stationary bicycle. [3]

Results:

In the Three-Community Study, “a statistically significant reduction was achieved in the composite risk score for cardiovascular disease as a result of significant declines in blood pressure, smoking and cholesterol levels. This risk score decreased approximately 25% for the media-only community and 30% for the community in which media were supplemented by face-to face instruction.” [2] In Tracy, there was a minimal decrease in risk score (less than 5% for both the total and high-risk participants). [1]

In the Five-City Project, smoking rates decreased by 14% in proportion of smokers compared to control communities. The intervention cities also experienced a 15% decrease in risk score based on improvements in blood pressure, physical activity, and cholesterol. [2] Numerous sub-campaigns including a curriculum for fourth, seventh and tenth grade students were found effective in increasing awareness of nutrition, physical activity and smoking cessation as essential to heart health. [2]

Discussion:

Strengths of the studies included random sampling from an open population and ability to assess effectiveness of a community intervention. [1] While the curriculum, counseling and media campaigns were successful in the Stanford Community Trials, the authors were skeptical about the ability to implement such efforts on a national scale. Concerns articulated included lack of trained staff, overstretch of county health departments and the decentralization of public schools. [2] Outside reviews emphasized the useful tests of social learning theory but the relatively high cost and small demonstrable change in health behavior at the community level. Reference #4 below sums the results from the three U.S. Community Demonstration Projects indicating the low power and difficulty of comparing the effect of such campaigns among small numbers of relatively healthy communities that are already undergoing large changes in health mores. (HB)