Since we wrote our last article on cholesterol, more information has been published and we want you have all of the facts. Certainly my cardiologist has changed my medication to keep LDL at a very low level, lower than we tolerated before these newer studies were published.
Why does this topic warrant revisiting? We want to share risk factors for coronary artery disease in type 2 diabetics from the United Kingdom Prospective Study. In this study 3,055 patients with a mean age of 52 years who were diagnosed with type 2 diabetes were followed for 7.9 years.
Of these, 335 patients developed coronary heart disease. A quintet of potentially modifiable risk factors for coronary artery disease existed in this group. Most important was increased concentration of LDL cholesterol and decreased HDL cholesterol. Also in evidence was raised blood pressure, hyperglycemia and smoking.
Second, we want to share with you some interesting facts that we have read in various articles about cholesterol in the general population. We will then share with you some facts from the position paper on the management of dyslipidemia in adults with diabetes. We will leave it you to then share your concerns with your physician so that you remain as healthy as possible.
Even though the average American has lowered his or her cholesterol, the average still remains in the borderline range – slightly over 200 mg/dl. Although people are eating less fat than in years past, we as a culture are becoming more obese.
Those who are asked to take cholesterol lowering medications, often stop for various reasons. For one thing there may be few symptoms, and many people are more afraid of cancer so they don’t take this seriously, and because this is a chronic disease many people get bored or decide they have better ways to spend their funds than on expensive medications.
The numbers of normal cholesterol levels
It’s important to know your numbers.
If you’re healthy your numbers should be:
- total cholesterol: below 200 mg/dl
- total triglycerides: below 200 mg/dl
- HDL cholesterol: above 45 mg/dl
- LDL cholesterol: below 130 mg/dl
If you have coronary artery disease:
- total cholesterol: below 200 mg/dl
- total triglycerides: below 200 mg/dl
- HDL cholesterol: above 35 mg/dl
- LDL cholesterol: below 100 mg/dl
Current genetic research has recently found the gene (called ABC) that controls HDL cholesterol. Hopefully, in the next years, a medication will be found that will boost protein that removes cholesterol from artery walls leading to transport out of the body by HDL.
Other research has found a gene called MTP which seems to cut production of LDL cholesterol. Still other research shows that 10% of high cholesterol cases are related to thyroid function. or hypothyroidism. One of the observed side effects of hypothyroidism is an elevation in LDL cholesterol, better known as the “bad” cholesterol. Elevated LDL has been associated with coronary artery disease and peripheral vascular disease. In the most severe cases of hypothyroidism the disease causes a marked elevation in triglyceride levels.
Recent studies point to the need that all patients with hypercholesterolemia should have tests of their thyroid function since a small percentage of these persons will have hypothyroidism contributing to their cholesterol problem. Treatment with thyroid hormone will lower cholesterol levels in those patients with an abnormal cholesterol from hypothyroidism.
Long-standing, untreated hypothyroidism can lead to permanent damage to the coronary arteries and other blood vessels. Therefore, it is important to treat hypothyroidism and monitor cholesterol levels closely.
The risk factors of high cholesterol
There are significant risk factors for developing high cholesterol. These are mostly controllable:
- inactivity: Lack of exercise may lower your levels of good cholesterol HDL.
- obesity: Excess weight increases your level of triglycerides and can lower HDL. It can also increase your level of very-low-density lipoprotein cholesterol.
- diet: Eating a high-fat. high cholesterol diet contributes to an increase in blood cholesterol level. Even polyunsaturated fats are susceptible to oxidation and over time speeds buildup of plaque inside arteries.
Other factors that increase your likelihood of high cholesterol:
- smoking: This damages the walls of your blood vessels making them prone to the accumulation of deposits. It also lowers levels of HDL as much as 15%.
- high blood pressure: This damages the walls of your arteries so that it becomes easier to accumulate fatty deposits.
- type 2 diabetes: Chronic high blood glucose levels leads to narrowing of arteries.
- family history of atherosclerosis: If a close relative (parent or sibling) has developed atherosclerosis before age 45, high cholesterol levels place you at a greater risk than average for developing atherosclerosis.
The position paper on management of lsylipidemia in adults with diabetes is especially important for those with type 2 diabetes, because type 2 is associated with a two to fourfold excess risk of coronary heart disease(CHD).
The relationship between type 2 diabetes and cardiovascular disease
The relationship between uncontrolled diabetes to macrovascular disease is not completely understood. The reason for this is that researchers have found an increased risk for cardiovascular disease before the diagnosis of type 2 diabetes.
Clearly this points to a need for aggressive screening for diabetes combined with improved glycemic control. The most common pattern of dyslipidemia in type 2 diabetics is elevated triglyceride levels and decreased HDL cholesterol levels.
Type 2 diabetics typically have a preponderance of smaller, denser LDL particles, which possibly increases atherogenicity even if the absolute concentration of LDL cholesterol is not significantly increased. It is also known that the mean triglyceride level in type 2 diabetes is <200mg.dl, and 85-95% of patients have triglyceride levels below 400mg/dl.
In terms of research for understanding the amount of lipids and lipoproteins as predictors of CHD in type 2 diabetes, the results are scarce. No trials on the effects of lipid-lowering agents on subsequent CHD in diabetic patients has been done so far.
However, some studies did include a small number of those with type 2 diabetes and in all, medication had a positive effect on CHD. What is known is that all glucose lowering agents lower triglyceride levels, however they have only a modest effect on raising HDL.
LDL cholesterol may decrease modestly (up to 10-15%) with the achievement of glycemic control. Since improved glycemic control may also lower triglyceride levels, it might also cause a favorable change in LDL composition.
Optimal LDL cholesterol levels in diabetics
In diabetic persons optimal blood levels are:
- Optimal LDL cholesterol levels in diabetics are <100 mg/dl Optimal HDL cholesterol levels in diabetics are >45 mg/dl
- Optimal triglyceride levels in diabetics are <200 mg/dl
Because of the frequent changes in glycemic control in diabetic patients and their effects on levels of lipoprotein, levels of LDL, HDL, total cholesterol, and triglyceride should be measured yearly in adult type 2 diabetes patients. If values fall below in lower-risk levels, assessment may be repeated every 2 years. In children with diabetes, consideration should be given to measuring lipoproteins after age 2.
The recommendations for treatment of elevated LDL cholesterol generally follows guidelines of National Cholesterol Education Program and the American Diabetes Association with the following caveats: Pharmacological therapy should be initiated after behavioral interventions are used.
However, in patients with clinical coronary vascular disease (CVD) or very high LDL (>200 mg/dl), pharmacological therapy should be initiated at the same time behavioral therapy is started.
Type 1 diabetic and LDL levels
Type 1 diabetic patients who are in good control tend to have normal levels of lipoprotein. Their composition of lipoproteins may be abnormal but the effects of this on CHD is unknown. It does, however, seem reasonable that if type 1 diabetic patients have high LDL levels that they should meet the same goals as those for type 2 diabetic patients. The position paper suggests that improved glycemic control may be more important in type 1 diabetic patients than type 2 in the reduction of CHD.
The paper concludes that aggressive treatment of diabetic dyslipidemia will probably reduce the risk of CHD in persons with diabetes. Primary therapy should be directed to reduce LDL levels. The initial therapy for hypertriglyceridemia is to improve glycemic control.
Treatment of LDL cholesterol is considered first priority for pharmacological therapy of dyslipidemia for a number of reasons. The initial therapy is behavioral with weight loss, increased physical activity, and moderation of alcohol consumption.
In severe hypertriglyceridemia (>1,000mg.dl) severe dietary fat restriction ( <10% of calories) in addition to pharmacological therapy is necessary to reduce the risk of pancreatitis. After the achievement of optimal glycemic control the physician may consider adding a fibric acid.
Above 400 mg/dl triglyceride levels pharmacological treatment is warranted. In some studies high doses of statin therapy were moderately effective in reducing triglyceride levels in markedly hypertriglyceridemia subjects (triglyceride >300 mg/dl).
Ask your physician about classes of medications which include resins (Questran and Colestid), triglyceride-lowering drugs (Lopid, Tricor and Niacin), and Statins (Lescol, Mevacor, Zocor, Pravachol, Lipitor and Baycol).
The moral of all of these facts is to know your numbers and talk to your doctor to make sure you are within the guidelines for your own good health. Do talk over how to manage your diet and discuss “good ” fats, fish oils, complex carbohydrates, photochemical packed foods, black tea, red wine, soy products and any other foods that you read about.
Perhaps they will fit into your diet and be of help; perhaps they won’t. Don’t start on your own as they all have calories and you don’t need those extra calories. Something may have to be taken away from your meals to incorporate these.
We are pleased to bring you this type of information. Please feel free to contact us if you have further questions and we’ll try to answer them. If you have ideas for future articles, just let us know.