A simple linear model for the effect of changes in metabolic risk factors on coronary heart disease

Objectives. The risk of having one or more metabolic risk factors in the development of coronary heart disease (CHD) is well estimated, but it still remains to be shown which influence any given change in the number of risk factors has on the overall risk of CHD. Design. In this prospective cardiovascular population study, 10 194 participants were examined twice with a 5-year interval for metabolic risk factors such as obesity, hypertension, hypercholesterolaemia and diabetes mellitus. Results. During 14 years of follow-up, 1724 incident cases of CHD were identified, 973 in men and 751 in women. The effect of an increase in the number of metabolic risk factors during a 5-year interval on the relative risk of CHD could be determined to be statistically significant for both genders. But only for men, the effect of a decrease in the number of metabolic risk factors was statistically significant during the same time interval. Hence, by statistical analysis, a simple linear model could be constructed for men with two linear trend parameters, one corresponding to the number of metabolic risk factors at the first examination and one corresponding to the change in the number of metabolic risk factors from the first to the second examination. The parameters were 1.50 (1.39-1.63); P < 0.001 and 1.29 (1.18-1.41); P < 0.001, respectively. Conclusions. This study suggests that it is possible to fit a simple linear model for the effect of changed number of metabolic risk factors on the risk of CHD.