Like the literary split personality, it has a good side
because it is needed for certain important body functions.
But for many Americans, cholesterol also has an evil side.
When present in excessive amounts, it can injure blood
vessels and cause heart attacks and stroke.
The body needs cholesterol for digesting dietary fats,
making hormones, building cell walls, and other important
processes. The bloodstream carries cholesterol in particles
called lipoproteins that are like blood-borne cargo trucks
delivering cholesterol to various body tissues to be used,
stored or excreted.
But too much of this circulating cholesterol can injure
arteries, especially the coronary ones that supply the
heart. This leads to accumulation of cholesterol-laden
"plaque" in vessel linings, a condition called
atherosclerosis.
When blood flow to the heart is impeded, the heart muscle
becomes starved for oxygen, causing chest pain (angina).
If a blood clot completely obstructs a coronary artery
affected by atherosclerosis, a heart attack (myocardial
infarction) or death can occur
Heart disease is the number one killer of both men and women
in this country. More than 90 million American adults, or
about 50 percent, have elevated blood cholesterol levels,
one of the key risk factors for heart disease, according to
the National Heart, Lung, and Blood Institute's National
Cholesterol Education Program.
While the institute estimates that heart disease killed
nearly half a million in 1996, the most recent year for
which figures are available, a study published in the New
England Journal of Medicine in September 1998 says heart
disease deaths have declined steadily over the last 30
years.
Indeed, between 1990 and 1994, heart disease deaths
decreased by 10.3 percent, the study says. From this and
other studies, it appears that this is due largely to
improvements in medical care after heart attack, a reduction
in the number of repeat heart attacks, and better prevention
of heart disease development.
A key factor in this drop is that the public, patients and
doctors today are better informed about the risks associated
with elevated cholesterol and the benefits of lifestyle
changes and medical measures aimed at lowering blood
cholesterol.
"Public health initiatives such as the National
Cholesterol Education Program have raised consumer
awareness, promoted effective interventions, and have likely
contributed to the reduction in heart disease deaths," says
David Orloff, M.D., of the Food and Drug Administration's
division of metabolic and endocrine drug products.
Another factor in the drop may be a relatively new class of
drugs called statins. These have provided doctors with an
arsenal of therapies to lower elevated blood cholesterol
levels, often dramatically. To date, FDA has approved six
statin or cholesterol lowering drugs. Which we'll cover in
more detail in upcoming articles.
