Cholesterol and Diabetes
Diabetes greatly increases the risk of developing cardiovascular disease (CVD). Since high cholesterol levels also increase CVD risk, it's important to keep cholesterol levels under control if you have diabetes.
Cholesterol consists of three main components: high-density cholesterol (HDL, good cholesterol), low-density cholesterol (LDL, bad cholesterol), and triglycerides.
According to the new American Diabetes Association (ADA) guidelines, high LDL cholesterol is a common problem for people with diabetes. Also referred to as dyslipidemia, this condition greatly increases the risk of developing CVD.1
Cholesterol Numbers for People with Diabetes
It's important to know your cholesterol numbers.
If you don't have prexisting CVD, your numbers should be:
- total cholesterol: < 200 mg/dL
- total triglycerides: < 200 mg/dL
- HDL cholesterol (the "good" cholesterol): > 45 mg/dL
- LDL cholesterol (the "bad" cholesterol): <130 mg/dL
If you have CVD already, your numbers should be:
- total cholesterol: < 200 mg/dL
- total triglycerides: < 200 mg/dL
- HDL cholesterol: > 35 mg/dL
- LDL cholesterol: < 100 mg/dL
Current Guidelines: New Focus on Statins
The ADA now recommends that all people with diabetes take the cholesterol lowering drugs—statins—in addition to lifestyle therapy (meal planning changes and exercise) to reduce the likelihood of developing heart disease (eg, heart attack and stroke).2
"Statins are the drugs of choice for LDL cholesterol lowering and cardioprotection," the ADA stated. Patients with diabetes should either be prescribed a moderate or intensive statin therapy, depending on their age and the presence of CVD risk factors or CVD diagnosis, according to the ADA's revised guidelines. This is a change from past policy, which only called for statins if LDL cholesterol levels alone were abnormal.
Unless you are under the age of 40 and have no CVD risk factors, the ADA recommends you take a moderate or intensive statin therapy. If you are not already taking a statin, you should speak to your healthcare provider about this, especially if you have any CVD risk factors.
CVD Risk Factors
- LDL cholesterol level >100 mg/dL (2.6 mmol/L)
- High blood pressure (hypertension)
- Overweight or obese
These risk factors for developing high cholesterol can be controlled:
- Inactivity: Lack of exercise may lower your levels of good cholesterol HDL.
- Obesity: Excess weight increases your level of triglycerides and can lower HDL.
- Meal Planning: Eating a high-fat, high cholesterol diet contributes to an increase in blood cholesterol level.
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.
Diastolic Blood Pressure
Monitoring blood pressure is also important for people with diabetes, as hypertension is a common CVD risk factor. The ADA also changed its guidelines for a less stringent diastolic blood pressure score for patients with diabetes—the new goal is < 90 mmgHg.
However, an even lower blood pressure out of prehypertension range (< 80 mmHg) is still encouraged, especially for younger patients or those with kidney disease and elevated urine albumin excretion.3 People over the age of 40 with any of these CVD risk factors, or who have had a cardiovascular event in the past, are recommended high doses of statins. The ADA also recommends that all people with diabetes should have their cholesterol tested at least annually, regardless of their CVD risk status.
Side Effects of Statins
Most people tolerate statins well, but there are some common side effects, including:
• Aching muscles, soreness, muscle weakness
• Loss of Sleep
If you find yourself suffering from any of these side effects, speak to your healthcare provider. They may decide to place you on a different form of statin or change your dosage level. Statins can also lower LDL-cholesterol levels very differently depending on the individual,4,5 so having to adjust the dosage is normal.
Do Statins Raise Blood Glucose?
Statins are known to increase blood sugar levels, and some research has suggested this could increase the risk of diabetes diagnosis.6,7 However, the benefits of using statins to decrease CVD risk seem to far outweigh this possible side effect.8
"Some evidence suggests that patients at risk for developing diabetes may progress more quickly to diabetes once they are on a statin, but overwhelming evidence supports the fact that statins confer a huge mortality benefit to patients with diabetes," said Richard W. Grant, MD, MPH, a research scientist at Kaiser Permanente in Oakland, California, and chair of the ADA's Professional Practice Committee.
People with diabetes should not change their glucose monitoring practices when starting a statin therapy, either, Dr. Grant said.
"Because of the very high lifetime risk of CVD in people with type 2 diabetes, there is a growing consensus among both diabetologists and cardiologists that statin therapy should be commenced as early as possible after the diabetes has been diagnosed," said Philip J. Barter, MBBS, PhD, a professor at The Heart Research Institute in Sydney, Australia.
"The issue is greater with intensity of statin therapy, although the reduction in risk of having a CV event is very much greater than the (small) risk of developing diabetes," Dr. Barter said.
In 2011, Diabetic Lifestyle reported on a study led by Dr. Barter that looked at combining statin therapy with Torcetrapib, a type of drug referred to as a cholesterol ester transfer protein (CETP) inhibitor, which seemed to have improved fasting blood glucose, insulin levels, and insulin resistance in diabetes patients.
"The effects of CETP inhibitors on glycemic control in people with diabetes was quite clear during treatment with torcetrapib. It remains to be seen whether this was unique to torcetrapib or whether it is a consequence of the HDL raising induced by CETP inhibition," Dr. Barter said.
Studies are still ongoing in this area. If successful, it could be a novel combination therapy to lower LDL cholesterol, decrease CVD risk, and improve blood glucose.
"If CETP inhibition is shown to reduce CV risk and if CETP inhibitors other than torcetrapib improve glycemic control in diabetics, the combination of statin plus CETP inhibition would be a logical approach to reducing (cardiovascular) risk in patients with diabetes."
People with type 1 diabetes 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 people with type 1 diabetes have high LDL levels, they should meet the same goals as those set for type 2 patients. Improved glycemic control may be more important in type 1 diabetes patients than type 2 in the reduction of CHD.
Cholesterol and Diabetes Conclusion
The moral of all of these facts is to know your numbers and talk to your healthcare provider 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. A Registered Dietitian Nutritionist (RDN) can help individualize a meal plan for you.