High Cholesterol and Medical Drug Treatments
Introduction
With cholesterol testing at health fairs and drug stores, and with a breakdown of fat and cholesterol counts on all the packaged food we eat, you are probably well aware of the relationship between high cholesterol and heart disease. Yet, heart disease remains the leading cause of death in the United States; and you may not always eat the healthy, low-cholesterol diet that you should.
Because of the important relationship between high cholesterol and heart disease, all adults over the age of 20 years should have a fasting lipoprotein profile (a complete cholesterol profile--includes measuring total cholesterol, triglycerides, low-density lipoprotein(LDL) and high-density lipoprotein (HDL)) checked at least every 5 years. This should occur more often if a family history of coronary heart disease exists. Most children do not need to have their blood cholesterol level checked.
What is it?
Cholesterol is a soft, waxy, fat-like substance the body needs for cells to grow and regenerate. Cholesterol comes from two sources: your body and the foods you eat. The body makes its own cholesterol in the liver, and it only takes a small amount of cholesterol in the blood to meet your body's needs. However, because cholesterol can be found in foods such as red meats, whole milk dairy foods, and egg yolks, eating too much dietary cholesterol can make your blood cholesterol levels increase. Too much cholesterol circulating in the bloodstream is known as hypercholesterolemia.
Hypercholesterolemia increases the risk of heart disease because it can lead to atherosclerosis, a condition in which fat and cholesterol are deposited on the walls of the arteries. Atherosclerosis can occur in arteries throughout the body, including the coronary arteries (those feeding the heart). In time, narrowing or clogging of the coronary arteries by atherosclerosis can produce the signs and symptoms of heart disease, including angina (chest pain) and heart attacks.
When cholesterol builds up in arteries, it forms plaques which block blood flow and deny oxygen to the heart.
There are a number of types of cholesterol:
- Low-density lipoproteins (LDLs) are often referred to as "bad cholesterol" because LDL cholesterol carries cholesterol to the body?s tissues, including the arteries. Elevated levels of LDLs can lead to heart disease.
- High-density lipoproteins (HDLs) are referred to as "good cholesterol" because HDL cholesterol carries cholesterol from the tissues to the liver for removal from the body. Elevated levels of HDLs can prevent heart disease.
- Triglycerides are a storage form of fat. Elevated levels of triglycerides may also increase the risk of heart disease.
What causes it?
Many factors appear to contribute to the development of high cholesterol:
- Heredity--Your genes partly influence how your body makes and handles cholesterol.
- Your diet--A high intake of saturated fat, dietary cholesterol, and excess calories can cause your cholesterol levels to increase. Being overweight can increase your LDL levels and decrease your HDL levels.
- Age and gender--Cholesterol levels begin to increase in both men and women beginning around 20 years of age. Premenopausal women usually have lower levels of cholesterol when compared with men of the same age. After menopause, a woman's LDL cholesterol level typically goes up, as does her risk for heart disease.
- Other medical conditions--Conditions such as diabetes, liver disease, thyroid disease, or kidney disease can cause elevated cholesterol.
- Lack of physical activity--Increased physical activity lowers LDL and raises HDL levels. Lack of exercise can cause the opposite.
Who has it?
It is estimated that 100 million American adults have total blood cholesterol values of 200 mg/dL and higher--desirable total cholesterol levels are below 200 mg/dL. This desired level may be lower for those who have already had a heart attack or for those at risk for heart disease because they smoke, have hypertension, or have diabetes. There are about 13.2 million Americans with known coronary heart disease and about 8.7 million adults without formally diagnosed coronary heart disease.
Interestingly, about 10% of adolescents age 12 through 19 have total blood cholesterol levels of greater than 200 mg/dL. This may be due to the increasing rates of obesity among children and adolescents. There is compelling evidence that the development of atherosclerosis begins in childhood and progresses slowly into adulthood.
The good news is that medications and healthier lifestyles are making a difference. Today, the number of Americans with a desirable blood cholesterol level (less than 200 mg/dL) has risen to over 51% and the average total cholesterol in this country has fallen from 220 mg/dL in the early 1960s to 203 mg/dL in 2002. But, we still have a long way to go.
What are the risk factors?
A high fat diet, lack of exercise, and a family history of high cholesterol or heart disease will all increase your risk for high cholesterol and heart disease. If you have high cholesterol, the additional risk factors for developing heart disease include the following:- Increasing age: Being male greater than 45 years old or being female greater than 55 years old (or having premature menopause without estrogen replacement therapy)
- Heredity: A family history of heart disease at a young age(that is, having a father or brother who had a heart attack or died of heart disease before the age of 55 years or having a mother or sister who had a heart attack or died of heart disease before the age of 65 years)
- Currently smoking cigarettes: Smokers' risk of heart attack is more than twice that of nonsmokers. Cigarette smoking is the biggest risk factor for sudden cardiac death: smokers have two to four times the risk of nonsmokers.
- High blood pressure: High blood pressure increases the heart's workload, causing the heart to enlarge and weaken over time.
- Low HDL cholesterol (less than 40 mg/dL): High levels of HDL or "good cholesterol (greater than 60 mg/dL) help to lower risk for heart disease.
Additional Factors that May Increase Risk
- Diabetes: Two-thirds of people with diabetes die of some form of heart or blood vessel disease. If you have diabetes, it's critically important for you to monitor and control any other risk factors you can.
- Obesity/Overweight: People who have excess body fat are more likely to develop heart disease and stroke even if they have no other risk factors. Obesity is unhealthy because excess weight increases the strain on the heart.
- High homocysteine levels: Homocysteine is an amino acid in the blood. Initial studies have found an association with high blood levels of homocysteine and an increased risk for heart disease. Homocysteine levels are strongly influenced by dietary intake of folic acid and B vitamins. Insuring adequate intake of these vitamins may help lower homocysteine levels. Ask your doctor if you should have your homocysteine levels tested. Homocysteine testing is done via a simple blood test.
Metabolic Syndrome, a collection of several health risks and problems, can place you at greater risk of developing heart disease, stroke, and diabetes. It is estimated that 1 in 5 Americans has metabolic syndrome, including 43.5% of people 60 to 70 years of age. Although the cause is unknown, researchers believe that it's related to many factors including diet, family history, and the amount of exercise a person gets. Diagnosis of this syndrome includes 3 or more of the following risk factors:
- A waistline more than 35 inches for men or 30 inches for women measured across the belly.
- Blood pressure of 130/85 mmHg ("130 over 85")or more
- A triglyceride level more than 150 mg/dL
- A fasting blood sugar level more than 110 mg/dL
- A high density lipoprotein level (HDL; also known as the good cholesterol) less than 40 mg/dL for men or less than 50 mg/dL for women
What are the symptoms?
Before the onset of heart disease, high cholesterol does not usually produce symptoms in and of itself. Without obvious health effects or symptoms, the average person has a hard time making needed diet and exercise improvements. The following are signs or results of high cholesterol:
- Coronary heart disease
- Heart Attack or stroke
- Peripheral arterial disease (narrowing of the blood vessels that deliver oxygen-rich blood to the legs, abdomen, pelvis, arms or neck)
- Inflammation of the pancreas
But any heart patient will tell you, the time to make changes is long before chest pain hits. When "bad" cholesterol blocks arteries in a condition called atherosclerosis, the results can be debilitating and even fatal.
How is it treated?
Treatment of high cholesterol is aimed at lowering the low-density lipoproteins (LDL) or "bad cholesterol," lowering triglyceride levels, and increasing the high-density lipoproteins (HDL) or "good cholesterol." Decreasing total cholesterol by 10% can result in a 30% reduction in coronary heart disease incidence. For every 1% decrease in LDL (bad cholesterol levels), heart disease rates drop 2%. On the other hand, for every 1% decrease in HDL, there is a 2 to 3% increase in the risk of heart disease.
A low fat/low cholesterol diet and exercise are essential in helping to lower cholesterol and to maintain low cholesterol levels. While drug therapy is often needed to lower cholesterol, diet and exercise are additionally recommended to help the drug therapy lower and control cholesterol levels. Patients with established cardiac disease and multiple risk factors (metabolic syndrome, diabetes, or smoking) are sometimes given more intense lifestyle changes.The decision to start a patient with dietary therapy or drug therapy is usually based on a patient's LDL cholesterol levels, presence of heart disease, and risk factors. Your doctor should calculate your "10-year risk" (also known as a Framingham Risk) for developing heart disease and use that risk estimation to decide if and when to start cholesterol-lowering therapy either through dietary modifications or medications.
Drug Therapy For the initial drug treatment of hypercholesterolemia, HMG-CoA reductase inhibitors (also called "statins") are often used because of their effectiveness and low incidence of side effects. Currently, six statin drugs are available. The choice of which to use will depend on how much cholesterol reduction you need, doctor's preference, and prescription insurance benefits. Studies have shown that certain high risk patients, such as those with diabetes, benefit from cholesterol lowering therapy with statins.
Other drug classes that may be used to treat hypercholesterolemia include bile acid resins, nicotinic acid, fibric acid derivatives, and cholesterol absorption inhibitors. Some of these drugs can be used in combination if a further reduction in cholesterol is needed.
If you specifically have elevated triglyceride levels, a fibric acid derivative or niacin may be most effective for you. Both medications work by decreasing the liver's production of triglycerides. Additionally, fibric acid derivatives (or "fibrates") such as gemfibrozil also increase HDL-C (good cholesterol) production.
Bile acid resins are mainly used in young adults with hypercholesterolemia or in combination with another cholesterol-lowering medication. These drugs interact with several medications including carbamazepine, gemfibrozil, and thyroid medication as well as several blood pressure medicines and antibiotics. These medications should be administered at least 1 to 4 hours before or 4 to 6 hours after these cholesterol lowering agents.Cholesterol absorption inhibitors are a new class of cholesterol lowering agents and work together with statins to lower cholesterol. This class of drugs works to lower blood cholesterol levels by absorbing excess cholesterol (from foods) in the intestines and thus blocking cholesterol's entry into the bloodstream. In a study published by the Mayo Clinic in May 2005, it was found that the addition of Zetia (a cholesterol absorption inhibitor) to statin therapy may cause a further reduction in a patient?s cholesterol levels. It is thought that this reduction may be the result of the two drugs working together but at different areas of the cholesterol production pathway. In fact, one pharmacy manufacturer combined Zetia with a commonly used statin known as Zocor. This combination product is called Vytorin. However, as with any medications it is recommended that you ask your doctor if this drug or combination of drugs is appropriate for you.