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Lowering cholesterol levels by eliminating eggs and fat is not the whole story, of course. Cholesterol levels are influenced by a number of factors, from age to genes, some of which cannot be controlled at all. The first is simply being an adult. Almost everybody has very low levels of cholesterol at birth, with LDL measuring around 50 mg per deciliter of blood. But by the time most people reach adulthood, they have at least twice that amount. "One of our problems as a species," says Virgil Brown, a cardiologist at New York City's Mount Sinai Medical Center, "is that we don't remove LDL as fast as other animals."
Gender also has an effect. Males and females start out with the same cholesterol levels, but around puberty boys experience a 20% to 25% drop in protective HDL and an ominous rise in LDL. This difference, researchers believe, is probably the reason why there are 60% fewer deaths from heart attacks in women than in men in the U.S. Race seems to play a part in how well the body handles cholesterol. Dr. Gerald Berenson, director of a long-term study in Bogalusa, La., has found that the changes in boys at puberty are more drastic in whites than in blacks. Says he: "It is as if white males are genetically programmed for early coronary disease."
In some cases, high cholesterol levels are caused by genetic defects. Molecular Geneticists Michael Brown and Joseph Goldstein, of the University of Texas Health Sciences Center in Dallas, have discovered a tiny structurea single moleculethat sits on the surface of cells and removes potentially harmful LDL cholesterol from circulation. About one in 500 Americans is genetically deficient in these structures, called LDL receptors, and, as a result, develops astronomically high levels of LDL cholesterol. People with this condition, called familial hypercholesterolemia (FH), have 25 times the normal risk of heart disease.
Such is the case for four out of five members of the Arnold Melman family of Ardsley, N.Y. The Melmans keep a chart tracing their rising and falling cholesterol and levels. Melman, a urologist, is the only member of his family who is free from such worries. His wife Lois and all three children have FH and must follow a strict lowfat, low-cholesterol diet. Lois and the two older children also take 30 gm a day of cholestid, a cholesterol-lowering drug similar to the cholestyramine used in the N.H.L.B.I. trial. Such drugs are expensive as well as unpleasant: as much as $200 for a month's supply. But, together with diet, they have helped the Melmans "make ourselves normal," as Lois puts it. Doctors hope that the results of the N.H.L.B.I. trial will convince pharmaceutical companies that there is a need and a market for less expensive, more palatable drugs.