A How-To Guide on Cholesterol

By Dick Thompson/Washington

Doctors too need prescriptions. Although the link between cholesterol and such ailments as heart disease and stroke has been growing stronger for nearly two decades, physicians have often been slow to put this lesson into practice. A 1986 survey, conducted by the National Heart, Lung and Blood Institute in Bethesda, Md., found that 50% to 75% of physicians failed to provide diet or drug treatment for patients with dangerously high cholesterol levels. Their inaction reflects both long-standing confusion over what constitutes a high cholesterol level and inexperience with the therapies.

To send a clear signal, a panel of experts assembled by the NHLBI last week called for all Americans over age 20 to have their cholesterol levels checked. The group also set forth the first well-defined national cholesterol-level standards for adults and spelled out precisely what physicians should do once ^ a patient's cholesterol level is determined. "Medical practice is going to undergo a major change on the basis of this report," said Panel Chairman DeWitt S. Goodman of Columbia-Presbyterian Medical Center in New York City.

The report delineates three cholesterol ranges (all measured in milligrams per deciliter of blood). Levels below 200 mg/dl are considered desirable, although people in this range are still urged to have their cholesterol rechecked every five years. Those with readings from 200 to 239 mg/dl are viewed as borderline cases and advised to watch their diet and be retested annually. Individuals with levels of 240 mg/dl or more are at high risk and require medical attention, including a second test to determine the ratio of "good" cholesterol (high-density lipoprotein, or HDL) to "bad" cholesterol (low-density lipoprotein, or LDL). People in the borderline range who have additional risk factors, such as smoking, being male, or having a family history of heart disease, are advised to follow the same routine as those at high risk.

The primary prescription for lowering cholesterol levels still reads like a California cafe menu: low-fat milk and dairy products, lean meat, few eggs and absolutely no animal fat or poultry skin. If cholesterol cannot be reduced with diet alone, the panel directed, physicians should prescribe such drugs as cholestyramine and colestipol, which act in the intestines and cause the body to utilize excess cholesterol. The much touted newer drug lovastatin, which works in the liver, where most of the body's cholesterol is manufactured, is mentioned as a second choice, since its long-term effects remain unknown. Based on the new standards, one in four adults may require diet modifications or drug therapy.

The new guidelines do not apply to children, who have different nutritional requirements; that matter will be addressed by a second national panel, to be convened next year. Nor do they address the problem of imprecise laboratory results. Last year 2.5 million Americans had their cholesterol levels checked, but measurements can be off by as much as 300%, depending on the test, the lab and even what the patient had to eat and drink in the previous twelve hours. The medical-laboratory industry is currently grappling with the problem by employing a "gold standard" developed by the Government in the hope that tests can be made consistent nationwide.

CHART: TEXT NOT AVAILABLE

CREDIT: TIME Chart by Nigel Holmes

. CAPTION: Percentage of adult Americans with high blood cholestrol levels*

DESCRIPTION: Shows percentage of adult Americans with high blood cholesterol levels by age groups for white men, black men, white women and black women.