Comparison of risk factors for coronary heart disease morbidity versus mortality

Owing to the often prohibitively high costs of medical examinations, or an absence of infrastructure for linkage of study members to morbidity registries, much aetiological research in the field of cardiovascular research relies on death records. Because they are regarded as being more distal to risk factor assessment than morbidity endpoints, mortality data are generally maligned in this context for seemingly providing less clear insights into aetiology. The relative utility of mortality versus morbidity registries is, however, untested. In a pooling of data from three large cohort studies whose participants had been linked to both death and morbidity registries for coronary heart disease, we related a range of established and emerging risk factors to these two methods of ascertainment. A mean duration of study member surveillance of 10.1 years (mortality) and 9.9 years (morbidity) for a maximum of 20,956 study members (11,868 women) in the analytical sample yielded 289 deaths from coronary heart disease and 770 hospitalisations for this condition. The direction of the age- and sex-adjusted association was the same for 21 of the 24 risk factor- morbidity/mortality combinations. The only marked discordance in effect estimates, such that different conclusions about the association could be drawn, was for social support, total cholesterol, and fruit/vegetable consumption whereby null effects were evident for selected outcomes. In conclusion, variation in disease definition typically did not have an impact on the direction of the association of an array of risk factors for coronary heart disease.