Plasma triglyceride and high density lipoprotein cholesterol as predictors of ischaemic heart disease in British men: The Caerphilly and Speedwell Collaborative Heart Disease Studies

OBJECTIVE: To assess the roles of plasma triglyceride and high density lipoprotein (HDL) cholesterol concentrations in predicting ischaemic heart disease. DESIGN: Two prospective cohort studies with common core protocols. SETTING AND PARTICIPANTS: Both cohorts are 100% samples of middle aged men. In Caerphilly the 2512 men were living within a defined area. In Speedwell the 2348 men were registered with local general practitioners. MAIN OUTCOME MEASURES: Fasting blood samples were taken at initial examination and plasma lipid concentrations were measured. Major ischaemic heart disease events were assessed from hospital notes, death certificates, and electrocardiograms. RESULTS: At first follow up, after an average of 5.1 years in Caerphilly and 3.2 years in Speedwell, 251 major ischaemic heart disease events had occurred. Men with triglyceride concentrations in the top 20% of the distribution had a relative odds value for ischaemic heart disease of 2.3 (95% confidence interval (95% CI) 1.3 to 4.1) compared with men in the bottom 20%, after adjusting for both plasma total and HDL cholesterol, and non-lipid risk factors. Men in the lowest 20% of the distribution of HDL cholesterol concentration had a relative odds value of 1.7 (95% CI 1.0 to 2.8) compared with the top 20%, after adjustment was made for total cholesterol and triglyceride concentrations, and non-lipid risk factors. These relations were not caused by beta blockers, which were being taken by 5% of the men. CONCLUSIONS: Plasma triglyceride concentration predicts major ischaemic events after allowance is made for total and HDL cholesterol concentrations and other risk factors. In these populations, triglyceride is a more important predictor than total cholesterol concentration.