at study entry. The study showed that fasting levels of triglycerides were an independent risk factor for CHD events, irrespective of serum levels of high density lipoprotein cholesterol (HDL-C) or low density lipoprotein cholesterol (LDL-C). Other independent predictors of CHD included serum levels of LDL-C and HDL-C, age, systolic blood pressure, cigarette smoking, diabetes mellitus, a family history of myocardial infarction and angina pectoris, but did not include total serum cholesterol levels. Individuals with an LDL-C/HDL-C ratio > 5 had a 19.2% chance of experiencing a CHD event in the next 8 years. Furthermore, if an LDL-C/HDL-C ratio > 5 was combined with hypertriglyceridaemia (> or = 2.3 mmol. l-1), the risk of CHD increased to 26.9%. The association between hypertriglyceridaemia and CHD events may be related to the presence of atherogenic, triglyceride-rich particles in plasma, such as LDL and very low density lipoproteins. High triglyceride levels may also predispose to thrombosis.
Triglycerides' role in coronary heart disease (CHD) risk assessment has long been debated. Although meta-analyses have suggested that triglycerides are an independent risk factor for CHD, a consensus has emerged that triglycerides more appropriately represent a biomarker of CHD risk rather than an independent risk factor. Ongoing studies will determine whether triglyceride lowering confers additional CHD benefit beyond that attained via low-density lipoprotein (LDL) cholesterol reduction. The American Diabetes Association presently recommends lowering elevated triglycerides as a secondary therapeutic target after LDL cholesterol, whereas other organizations, such as the National Cholesterol Education Program, recommend non-high-density lipoprotein cholesterol as the second priority after attaining the LDL cholesterol goal. However, reducing very high triglycerides (ie, > 500 mg/dL) remains a sufficiently high priority in affected individuals.
20 Evidence type: analysis of observational results from a randomized controlled trial
The Triglyceride Issue RevisitedFindings From the Helsinki Heart Study Leena Tenkanen, PhD; Kati Pietilä; Vesa Manninen, MD; Matti Mänttäri, MD Arch Intern Med. 1994;154(23):2714-2720. doi:10.1001/archinte.1994.00420230107012.
Results: Triglycerides occupied a central role in the pattern of associations of the factors studied; in particular, the associations with HDL-C level, blood pressure, and blood glucose level were without threshold values. The prevalence of high triglyceride level plus low HDL-C level was strongly associated with blood pressure and blood glucose level, while the prevalence of low HDL-C level alone was not. Only the subgroup with both high triglyceride and low HDL-C levels showed a substantial CHD risk, while those with low HDL-C levels alone or high triglyceride levels alone showed a marginal risk.
Conclusions: Our results suggest that triglycerides play a central mediating role in the occurrence of several CHD risk factors, especially those related to the insulin resistance syndrome. Because of these interdependencies, the question of an independent effect of triglycerides is not relevant, and when assessing CHD risk, triglycerides should be considered jointly with HDL-C
21 Evidence type: prospective analysis
Relation of High TG–Low HDL Cholesterol and LDL Cholesterol to the Incidence of Ischemic Heart Disease: An 8-Year Follow-up in the Copenhagen Male Study. Jørgen Jeppesen, Hans Ole Hein, Poul Suadicani, Finn Gyntelberg. Arteriosclerosis, Thrombosis, and Vascular Biology. 1997; 17: 1114-1120
High triglyceride (TG) and low HDL cholesterol (HDL-C) is the characteristic dyslipidemia seen in insulin-resistant subjects. We examined the role of this dyslipidemia as a risk factor of ischemic heart disease (IHD) compared with that of high LDL cholesterol (LDL-C) in the Copenhagen Male Study. In total 2910 white men, aged 53 to 74 years, free of cardiovascular disease at baseline, were subdivided into four groups on the basis of fasting concentrations of serum TG, HDL-C, and LDL-C. “High TG