Objective-To assess the roles of plasma triglyceride and high density lipoprotein (HDL) cholesterol concentrations in predicting ischaemic heart disease.Design increased risk of ischaemic heart disease.5 The first British study, however, to report on this association concluded that HDL cholesterol was not a major risk factor.6 A later report, based on a larger number of events and with a different method of analysis, revised that view and concluded that HDL cholesterol was important, but less so than total cholesterol concentration.7Raised concentrations of total triglyceride are associated with an increased risk of ischaemic heart disease. Most studies suggest that, in men, triglyceride is not an independent risk factor and that its relation with ischaemic heart disease is explained by the association of both with other factors, particularly total cholesterol and HDL cholesterol.78 This, however, has not been a universal finding and the role of triglyceride is still uncertain.9 Understanding of this role is complicated by the fact that in some studies triglycerides were measured after the subjects had fasted overnight, whereas in others the subjects had not.The Caerphilly and Speedwell studies recruited their joint population of 4860 middle age men between 1979 and 1983.10 Lipids were measured on fasting blood samples. In this report, the relations of 60

Abstract-Several studies have suggested that men with raised plasma triglycerides (TGs) in combination with adverse levels of other lipids may be at special risk of subsequent ischemic heart disease (IHD). We examined the independent and combined effects of plasma lipids at 10 years of follow-up. We measured fasting TGs, total cholesterol (TC), and high density lipoprotein cholesterol (HDLC) in 4362 men (aged 45 to 63 years) from 2 study populations and reexamined them at intervals during a 10-year follow-up. Major IHD events (death from IHD, clinical myocardial infarction, or ECG-defined myocardial infarction) were recorded. Five hundred thirty-three major IHD events occurred. All 3 lipids were strongly and independently predictive of IHD after 10 years of follow-up. Subjects were then divided into 27 groups (ie, 3 3 ) by the tertiles of TGs, TC, and HDLC. The number of events observed in each group was compared with that predicted by a logistic regression model, which included terms for the 3 lipids (without interactions) and potential confounding variables. The incidence of IHD was 22.6% in the group with the lipid risk factor combination with the highest expected risk (high TGs, high TC, and low HDLC) and 4.7% in the group with the lowest expected risk (PϽ0.01). A comparison of the predicted number of events in the 27 groups with the number of events observed showed that a logistic regression provided an adequate fit without the need to incorporate interactions between lipids in the model. Conclusions are as follows: (1) Serum TGs, TC, and HDLC are independently predictive of IHD at 10 years of follow-up. (2) Combinations of adverse levels of the 3 major lipid risk factors have no greater impact on IHD than that expected from their individual contributions in a logistic regression model. There was no evidence that men with low HDL/raised TGs were at significantly greater risk than that predicted from the independent effects of the 2 lipids considered individually. Key Words: coronary heart disease Ⅲ lipids Ⅲ triglycerides Ⅲ epidemiology Ⅲ interaction P lasma total cholesterol concentration is well established as a major risk factor for ischemic heart disease (IHD). 1,2 Within the past 20 years, HDL cholesterol has also been added as a major lipid risk factor independent of total cholesterol. 3,4 The role of triglycerides remains uncertain. 5,6 We have previously reported that at the first follow-up (5 years) of the Caerphilly and Speedwell Studies, triglyceride was an important and statistically significant predictor of IHD, even after adjustment for the major conventional nonlipid risk factors and for total and HDL cholesterol. 7 In the Copenhagen Male Study, 8 fasting triglyceride was an independent risk factor for subsequent IHD at the 8-year follow-up.In a report based only on the Caerphilly cohort at 10 years of follow-up, serum total cholesterol, HDL cholesterol, and triglyceride concentrations were independently predictive of IHD. 9 The effects of combinations of lipid factors on IHD have been examine...