The Battle of the Lipoproteins

By Christine Gorman

Cholesterol, the fatty substance that can clog arteries and induce heart attacks, plays a role in 85% of America's 550,000 annual deaths resulting from coronary heart disease. Ridding the bloodstream of the stuff through exercise and proper diet has become a standard health regimen. Last week, however, in a landmark paper in the New England Journal of Medicine, a group of Finnish scientists provided dramatic endorsement for a drug that drastically lowers the incidence of such disease, chiefly by raising the blood levels of a type of cholesterol.

The drug, called gemfibrozil, was originally approved for treatment of a pancreatic disorder. In a five-year study of more than 4,000 Finnish men, those treated with the drug suffered only two-thirds as many heart attacks and cardiac-related deaths. After three years of treatment, that fraction dropped to less than half. "This is the largest decrease in coronary disease seen in any trial," said Heikki Frick, a University of Helsinki scientist who took over the study in 1986 after its originator, Cardiologist Esko Nikkila, died in an auto accident.

The experiment was designed to show the differing effects of two distinct types of cholesterol: low-density lipoproteins, or LDLs, and a variant known as high-density lipoproteins, or HDLs. LDLs are the villains of cardiology: these complex molecules ferry cholesterol through the blood vessels, allowing life-threatening deposits to accumulate within artery walls. Each 1% decrease in LDL levels lowers the risk of heart disease 2%. The "good" HDLs work as garbage trucks, sopping up excess cholesterol and inhibiting arterial deposits. Basically, these two substances make up the total human blood- cholesterol level, an indicator that signals vulnerability to coronary illness.

The Finnish study shows that raising HDL levels also leads to a decreased risk of heart disease. Each of the participants, while otherwise healthy, was chosen for his high overall cholesterol level. Starting in 1981, doctors gave half the test group gemfibrozil, which, among other effects, increases HDL while moderately lowering LDL. The other half received a placebo. More than 82,000 visits to the clinic and 500,000 blood tests later, the LDL levels of the men given gemfibrozil had dropped 8% and their HDL levels had risen more than 10%.

Using complex statistical analyses, the Finns ruled out every potential cause for the benefit except higher HDL levels. Says Antonio Gotto, a cholesterol expert at Baylor College of Medicine in Houston: "The garden- variety person with cardiovascular disease, maybe 60% of heart-attack patients, has a low HDL level and only a moderately high LDL level. Changing HDL levels will be very important for them."

Physicians advise that the study results do not point to a miracle drug that will provide a risk-free cure for heart disease. For example, gemfibrozil seems to predispose people to develop gallstones. Moreover, doctors recommend that anticholesterol drugs, including lovastatin, which was approved by the Food and Drug Administration in September, should be used only as a last resort.

What the Helsinki study does make clear is that treatment to lessen the risk of heart attacks should concentrate as much on raising deficient HDL levels as on lowering dangerous LDL levels. That conclusion alone could point to longer life and better health for thousands each year.

CHART: TEXT NOT AVAILABLE

CREDIT: TIME Chart by Joe Lertola

CAPTION: Rx FOR THE HEART

DESCRIPTION: Number of heart attacks and cardiac-related deaths per year in the Helsinki study group. Color illustration: Medical attendants carrying stretcher.