Effect of community health education on plasma cholesterol levels and diet: the Stanford Five-City Project.

This paper examines the effects of community-wide health education on diet-related knowledge and behavior and on plasma cholesterol levels during an experimental field study in medium-sized cities in northern California. Samples of the population aged 12-74 years were drawn at baseline and every 2 years thereafter to obtain four cross-sectional surveys; participants aged 25-74 years are included in this paper (n = 6,814 or about 425 per city per survey). The baseline sample was asked to return to three follow-up surveys, also 2 years apart, constituting the cohort survey sample (n = 777). Diet was assessed by 24-hour recalls. In the serial cross-sectional survey samples, nutritional knowledge increased over time in both men and women in all cities; among women, this increase was significantly greater in the treatment cities. Plasma cholesterol declined significantly only in men and in neither sex was there evidence of a larger decline in treatment than in control cities. Dietary saturated fat intake tended to decline, but not significantly in either sex, and there was no evidence of treatment impact. Dietary cholesterol intake declined in both sexes. Results in the cohort samples were similar, except plasma cholesterol levels were unchanged over time in men and increased in women, and dietary saturated fat intake declined significantly among women. Secular improvements in knowledge of nutrition and in dietary cholesterol intake occurred during the early 1980s in both men and women in these four cities, while there was less consistent improvement in dietary saturated fat intake. Only nutritional knowledge among women achieved greater improvement in treatment cities than in control cities. Continued and greater change in nutrition probably requires more sustained effort and broader methods, including changes in the food supply.