Do Total and High Density Lipoprotein Cholesterol and Triglycerides Act Independently in the Prediction of Ischemic Heart Disease?

Abstract

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...

Birth Weight and Lipids in a National Birth Cohort Study

“…The mean value for total cholesterol in our sample was similar to fasting mean levels in the Dietary and Nutritional Survey of British Adults 50 and those in the Caerphilly study. 51 This is the first large birth cohort study to our knowledge to consider the association between birth weight and lipids in older adults. Our unadjusted estimate combined for both sexes is similar to that found in a recent meta-analysis of the association between birth weight and total cholesterol in which an increase in 1 kg of birth weight was associated with a 0.05-mmol/L reduction in total cholesterol.…”

Milk drinking, ischaemic heart disease and ischaemic stroke I. Evidence from the Caerphilly cohort

“…The men were seen first in 1979-1983 and they have subsequently been seen at 5-y intervals, that is they have been followed for 20-24 y. Details of the methods and reports on prediction of vascular disease by platelet, haemostatic, rheological, lipid and psychosocial factors have been reported elsewhere (Gallacher et al, 1999;Elwood et al, 2001a, b;Baker et al, 2002;Yarnell et al, 2001).…”

“…Evidence on prevalent vascular disease, ischaemic heart disease and/or stroke, including a 12-lead ECG, was recorded. Samples of fasting blood were taken for estimation of platelet (Elwood et al, 2001a), haemostatic (Baker et al, 2002), rheological (Elwood et al, 2001b), lipids (Yarnell et al, 2001), psychosocial (Gallacher et al, 1999) and other factors of possible relevance to vascular disease.…”

New Risk Factors for Atherosclerosis and Patient Risk Assessment

“…11 Triglycerides were also associated with CHD risk in the Caerphilly Heart Disease Study (CHDS), again independent of total cholesterol and HDL-cholesterol levels. 12 At the same time, no prospective, controlled trials have demonstrated the benefits of triglyceride lowering alone on clinical or cardiovascular outcomes, perhaps because available triglyceride-lowering agents also affect other lipid and lipoprotein concentrations. Although the PROCAM scoring scheme includes triglycerides as a major independent risk factor, the NCEP ATP III guidelines do not.…”