What can cause high cholesterol?
Elevated cholesterol levels can be caused by several factors, including heredity, poor diet, obesity, sedentary lifestyle, age, and gender (premenopausal women have lower cholesterol levels than men.) Of these causative factors, only heredity, age and gender cannot be controlled."Secondary" elevation of cholesterol
Some people have elevated cholesterol levels as a result of specific medical conditions, including diabetes, hypothyroidism (low thyroid,) obstructive liver disease, chronic renal (kidney) failure, and drugs (anabolic steroids, progesterone drugs, and corticosteroids.) In these patients, treating the underlying disorder often improves cholesterol levels.Who needs to be treated for elevated cholesterol?
Deciding when to treat can be based on two factors: lipid levels (total cholesterol, LDL, and HDL,) and the presence of additional risk factors, as follows.Desirable lipid levels:
Total cholesterol: Desirable levels are below 200 mg/dL. Total cholesterol is considered "borderline high risk" at levels between 200 and 239, and "high risk" at levels above 240. LDL cholesterol: Optimal LDL levels are less than 100 mg/dL. Near optimal levels are between 100 and 129 mg/dL. Levels between 130 and 159 are considered "borderline high risk;" and levels between 160 and 189 are considered "high-risk;" and levels of 190 and above are considered "very high risk." HDL cholesterol: HDL cholesterol levels below 41 mg/dL are considered too low.Additional risk factors that modify cholesterol goals:
- cigarette smoking
- diabetes
- hypertension (high blood pressure)
- low HDL cholesterol
- family history of premature heart disease
- age greater than 45 in men, or greater than 55 in women
- 10-year risk of heart attack greater than 20% The 10-year risk is calculated from a formula that takes into account the individual's the lipid levels and other risk factors. Click here for the NIH's on-line version of the 10-year risk calculator.
Based on these two items (i.e., lipid levels and presence of additional risk factors) treatment is recommended as follows:
For those with 0 - 1 risk factors:LDL target: 160 or lower. Lifestyle changes should be initiated for LDL > 159, and drug treatment for LDL > 189.For those with 2 or more risk factors:LDL target: 130 or lower. Lifestyle changes should be initiated for LDL > 129, and drug treatment for LDL > 159.
If heart disease is present or 10-year risk > 20%, or diabetes is present:LDL target: 100 or lower. Lifestyle changes should be initiated for LDL > 100, and drug treatment for LDL > 129.
What about treatment for high triglycerides?
The latest guidelines (May, 2001,) for the first time, recommend treating patients who have elevated triglyceride levels. This recommendation is based on recent analyses strongly suggesting that triglycerides are indeed an independent risk factor for coronary artery disease. The decision to treat is generally based on the triglyceride levels themselves. Normal triglyceride levels are less than 150 mg/dL. Borderline high levels are 150-199 mg/dl. High levels are 200 - 499 mg/dL, and very high triglyceride levels are greater than 500 mg/dL. For people with borderline or high triglyceride levels, treatment should emphasize weight reduction and exercise. Drugs are recommended for people with very high triglyceride levels. Most people who need treatment for high triglyceride levels have metabolic syndrome X.What other "special circumstances" deserve attention?
Patients with very high LDL cholesterol levels (greater than 189 mg/dL): These patients often have a genetic form of lipid disorder. Not only do they have a high risk of premature heart disease without aggressive therapy, but also their family members should be screened for elevated cholesterol levels, and those with high cholesterol levels also need to be treated. Patients with low HDL cholesterol levels (less than 40 mg/dL): The latest guidelines recognize low HDL levels as a strong independent risk factor for coronary artery disease. Many of patients with low HDL will have diabetes or "metabolic syndrome x." They are often overweight and physically inactive. Other causes of low HDL levels are smoking, very high carbohydrate diets (greater than 60% of calories), and drugs (anabolic steroids, progesterone, and beta blockers). Unfortunately, current drug therapy usually does not markedly increase HDL levels. Treatment for patients with low HDL levels is usually aimed at weight reduction, smoking cessation, exercise, and controlling other risk factors (such as hypertension, LDL cholesterol, and triglycerides.)Page 3 - Treating cholesterol and triglycerides
