Objectives: The aim was to rank coronary heart disease (CHD) risk factors according to their importance in predicting CHD morbidity and mortality using a scale-independent statistical approach.
Design: We studied 15 515 community-dwelling adults in a population-based cohort established during 1992-93 in Western Norway. Participants were 40-42 and 65-67 years old at baseline and were followed through 2006. Endpoints were non-fatal/fatal acute myocardial infarction (AMI) and CHD death. Each factor was rank transformed and scaled to the range 0-5 before estimation of Cox models. Hazard ratios (HR) may thus be interpreted as HR per quintile increment for each factor, and the magnitude of the HR was used to rank the risk factors according to strength.
Results: Total cholesterol and triglycerides were important risk factors for both CHD death and non-fatal/fatal AMI only in the middle-aged group. Risk factors were generally stronger in the middle-aged, except total homocysteine which was significantly associated with CHD death in the oldest group only. The only significant difference between men and women was found for single living which was an important risk factor for non-fatal/fatal AMI in middle-aged women but not in middle-aged men.
Conclusions: We have demonstrated a simple method for direct and scale-independent comparison of the strength of both categorical and continuous risk factors. The importance of individual risk factors differed substantially between the two age groups.