Risk factors changes and coronary heart disease in an observational study.

Data from the Seven Countries Study are analysed to examine the relationship between the observed incidence of Coronary Heart Disease in the second 5-year period of follow-up and the major entry risk factors and their changes over the first 5 years. The analysis, using the Multiple Logistic Function model, shows that changes in systolic blood pressure and smoking habits are significant factors associated with incidence, while changes in cholesterol and body mass index do not play this role. This conclusion applies to the population as a whole. A more detailed analysis, stratifying the population by estimated risk at entry and changes of risk over 5 years, shows that incidence is related to changes of risk in low and medium entry risk groups. Moreover, a univariate analysis of data limited to systolic blood pressure and cholesterol indicates that changes in blood pressure are related to incidence in the group with highest entry level of blood pressure, while changes in cholesterol are irrelevant to subsequent incidence.