The Multifactor Primary Prevention Trial in Göteborg, Sweden

Summary

All male inhabitants of the city of Göteborg, who were born between 1915–1922 and 1924–1925 were included in the trial, and were 47 to 55 years of age on entry to the study in 1970 to 1973. One-third of these men were randomly allocated to an intervention group, whilst the other two-thirds acted as controls. Men of all social classes, employed as wellas unemployed, health conscious as well as careless, were invited, with 75% of these responding to the invitation. The intervention group contained 10,000 men and the control group 20,000 men.

The intervention group were given advice on diet, both individually and in groups, the type of advice depending upon serum cholesterol level. Smokers were advised to stop smoking, and men with elevated blood pressure were treated with antihypertensive drugs.

Due to the large size of the groups and because they formed a random population sample, it was assumed that they had similar characteristics at the start of the trial. Risk factors were only measured in the intervention group at this time, followed by intervention. This design feature solved several ethical problems with regard to no treatment in the control group. These men were, however, subjected to health examinations and treatment as well as general health advice.

Risk factor levels were measured in the intervention group, and also in random subsamples (11%) of the control group after 4 and 10 years. Serum cholesterol, blood pressure and smoking decreased among men in both groups, and only slightly more in the intervention group. Antihypertensive drug treatment was given to 26% of the intervention group and 20% of the control group participants after 10 years.

No significant effect on total or cardiovascular mortality, or on the incidence of myocardial infarction or stroke was found. However, the effect of this intensive antihypertensive treatment on mortality and morbidity is indicated when the present results are compared to those of a previous population study in the same city.

A markedly higher mortality in the group of non-participants diluted the results considerably, and some characteristics of this group will be discussed in view of future possibilities of prevention efforts in the whole community.