Originally published in The Ottawa Citizen April 16, 2002
Original Title: Cholesterol Secrets
Many people are aware of the effects of elevated cholesterol upon their health. Indeed, the rates of heart disease and stroke continue to rise. Concomitant risk factors for heart disease like diabetes, hypertension, obesity, smoking and family history of heart disease and stroke complicate the picture.
Those with some or all these conditions use cholesterol-lowering agents as one means to reduce their risk of heart disease and stroke.
The medical terms reflecting the various cholesterol factors and lab measurements sometimes have a numbing effect as the patient tries to synthesize the results.
A lipid profile, the test used to diagnose hypercholesterolemia or a combination of elevated cholesterol and triglycerides, provides results for several lipid components; total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides.
LDL and HDL are proteins that carry cholesterol to specific destinations. They act as transport trucks. They are respectively known as “bad” and “good” cholesterol.
LDL’s function is to transport the cholesterol produced in the liver and deliver it to the cells in the body. Cholesterol is necessary to maintain the integrity of the cell walls and for the synthesis of certain hormones.
The majority of cholesterol is produced in the liver from a variety of foods laden with saturated fat. It is the reason why healthy diets are low in saturated fat.
Consistent consumption of foods containing saturated fat stimulates the liver to produce more LDL. An elevated LDL means that the liver is producing too much cholesterol.
The LDL is sent out into the body with too much cargo. This results in deposition of the extra cholesterol into the arterial walls causing blockages or plaques; hence LDL is the bad guy.
HDL picks up and transports cholesterol from the cells and bloodstream back to the liver to be destroyed thus its good-guy image.
Triglycerides are molecules that act as a storage reservoir for fatty acids. Fatty acids are used as an energy source for various metabolic processes. Elevated triglycerides contribute to the problems associated with elevated cholesterol levels.
Initial treatment for people who do not have risk factors for heart disease nor have had a heart attack is diet (foods containing polyunsaturated fats do not promote cholesterol synthesis thereby reducing LDL levels), exercise (to increase HDL levels), smoking cessation and lifestyle modification. After three to six months, medical therapy is indicated if the initial treatment is unsuccessful.
The recommendation for people who have a genetic predisposition to high levels of triglycerides is to use medication because lifestyle modifications other than smoking cessation have little effect.
The risk of heart disease is related to the tug of war between LDL and HDL. A measure of the risk of heart disease is calculated from the total cholesterol divided by the HDL (TC/HDL ratio). The lower the ratio, the better.
Ideally the net effect should be efficient removal of extra cholesterol from the bloodstream and the arteries. The goal is to reduce LDL and total cholesterol and increase HDL.
The results of the Heart Protection Study released in November 2001 may possibly change the treatment approach for heart disease and stoke prevention.
This five-year study had 20,000 volunteers between 40 and 80 years of age at high risk of coronary heart disease. The study wanted to know if cholesterol-lowering therapy was of use in specific groups of individuals where there was a lack of evidence of the benefits of drug treatment.
These groups were women, diabetics, people over 70 years of age, those with arterial disease not involving the heart, and those with average or below-average cholesterol levels.
Volunteers used either 40 milligrams of simvastatin per day as cholesterol-lowering therapy, or matching placebos. The study’s major findings include:
A one-third risk-reduction of heart attack and stroke with statin use reducing the need for arterial surgery, angioplasty (dilation of the coronary arteries) and amputations.
High-risk patients with normal cholesterol levels, women and men over 70 benefited from treatment.
About five years of simvastatin treatment typically prevents heart attacks, strokes or other major vascular events in:
- 100 of every 1,000 people who’ve previously had a heart attack
- 80 of every 1,000 people with angina or some other evidence of coronary heart disease
- 70 of every 1000 patients who’ve previously had a stroke
- 70 of every 1000 people with occlusive disease in leg or other arteries
- 70 of every 1000 people with diabetes
- A reduction of hospitalization risk because of worsening angina by about 30 fewer admissions per 1,000 treated for five years.
- Like high blood pressure, it takes time for elevated cholesterol levels to cause harm. Talk to your doctor about whether you need to be tested.
There is now evidence to expand treatment options for people who fall into one of the high-risk groups to prevent much hardship. That is what it is all about.
© Dr. Barry Dworkin 2002