MEASURING
THE T
he "good life"—a dinner of thick steaks or fire-red lobsters with melted butter—is one reason coronary heart disease ranks as the number one cause of death in most industrialized nations. After years of epidemiological studies pointing to a connection between cholesterol-rich diets and an increased risk of heart disease, the National Institutes of Health created the National Cholesterol Education Program (NCEP) in 1985 to convince Americans to change their eating habits. NCEP has also targeted family physicians, urging them to include serum cholesterol values, along with blood pressure and weight, as regular measures of health. Unfortunately, as the public health campaign began, a spate of articles in both the medical and the popular press questioned the accuracy and precision
FAT OF THE LAND
FOCUS of the cholesterol measurements the NCEP was asking physicians to routinely request. Without trustworthy numbers, family doctors might be reluctant to counsel dramatic lifestyle changes or prescribe medication for high cholesterol levels. Adding to the controversy, heart specialists are advocating an even more specialized test for cholesterol encapsulated in lipoproteins, the water-soluble protein coat required to transport the nonpolar lipid through the bloodstream. Research indicates that lowdensity lipoproteins (LDLs) can deposit cholesterol onto arterial walls, which may lead to atherosclerosis, whereas high-density lipoproteins (HDLs) may clear cholesterol from arteries. Clinical determination of these lipoproteins could provide an even better measure of heart disease risk than total cholesterol. But with no clear-cut marker of what differentiates LDLs from HDLs, clinical values for these cholesterol fractions vary widely. To clarify the situation, the NCEP
created its own subcommittee, the Laboratory Standardization Panel on Blood Cholesterol, to set standards and evaluate cholesterol testing. In 1988 the panel decreed that laboratory measures of total cholesterol should be accurate (bias) to
