The role of
lipids and
lipoproteins as important risk factors of
ischemic heart disease (IHD) is well established. With the demonstration in large-scale randomized clinical trials that aggressive lowering of
low-density lipoprotein (
LDL) cholesterol levels with
statins reduced the risk of IHD, the central role of
LDL cholesterol in the pathogenesis of IHD was proven. However, many IHD cases occur in people with normal
LDL cholesterol levels, and it is well known that the ability to predict who will develop IHD based on
LDL cholesterol levels alone is limited. Plasma
triglycerides and
high-density lipoprotein (
HDL) cholesterol are two other
lipid variables that over the years have attracted attention in cardiovascular epidemiology. Recently, much more attention has been paid to the relationship between
triglycerides,
HDL cholesterol, and risk of IHD because the combined
lipid profile of a high fasting
triglyceride level and a low
HDL cholesterol level is the characteristic
dyslipidemia in the
metabolic syndrome X. The objective of the present review article is to use data from the Copenhagen Male Study to demonstrate that, in men, fasting
hypertriglyceridemia is a strong risk factor of IHD independent of other major risk factors of IHD, and that the combined
lipid profile of a high fasting
triglyceride level and a low
HDL cholesterol level, the characteristic
dyslipidemia in the
metabolic syndrome X, is a very strong and important risk factor of IHD, at least as strong and important as a high
LDL cholesterol level.