A blood test, or the results of a blood test, that measures levels of lipids, or fats, including cholesterol and triglycerides. Factors such as your age, sex, and genetics influence your lipid profile. Certain aspects of your lifestyle, including your diet, level of physical activity, level of diabetes control, and smoking status, also affect your lipid profile. And some medical conditions can raise or lower cholesterol and triglyceride levels.
A lipid profile is a direct measure of three blood components: cholesterol, triglycerides, and high-density lipoproteins (HDLs). Cholesterol is a vital substance that your body uses to produce such things as digestion-aiding material, hormones, and cell membranes. It is both produced by the body and absorbed from some of the foods you eat. Cholesterol and triglycerides are transported in the blood by combinations of lipids and proteins called lipoproteins. HDLs, the so-called “good” or “healthy” cholesterol, are lipoproteins made mostly of protein and little cholesterol. HDLs can help to clear cholesterol deposits in blood vessels left by another blood component called low-density lipoproteins, or LDLs.
LDL levels may be calculated from the three directly measured lipids or may be more accurately measured by a direct test. LDLs and very-low-density lipoproteins (VLDLs) are the so-called “bad” cholesterols. Unlike HDLs, LDLs and VLDLs are high-cholesterol particles. While cholesterol is necessary for various bodily functions, too much cholesterol is harmful, since excess cholesterol can be deposited in blood vessel walls. These fat deposits can lead to atherosclerosis, or hardening of the arteries, and cardiovascular disease, the number one killer in the United States. High levels of triglycerides are also associated with an increased risk of heart disease.
People with Type 1 diabetes whose blood glucose levels are controlled tend to have lipid levels similar to people who don’t have diabetes and may even have higher levels of HDL, possibly because of the effects of insulin. People who have Type 2 diabetes, however, tend to have high levels of triglycerides and low HDL levels. And while people with Type 2 diabetes tend to have similar LDL levels as people who don’t have diabetes, their LDL particles seem to be smaller and more prone to causing damage. Premenopausal women who do not have diabetes tend to have better cholesterol levels than men, but this protective effect seems to be negated in women with diabetes. Both sexes show an increase in lipoprotein levels as they age.
The American Diabetes Association (ADA) recommends that people with diabetes who have lipid levels that need correction have a lipid profile taken at least annually. Because alcohol and food intake before the test can cause temporary elevations of cholesterol and triglycerides, it is necessary to fast for 9–12 hours before the test and to abstain from alcohol for 24 hours before.
According to the ADA, low-risk cholesterol levels in adults with diabetes are LDL levels below 100 mg/dl, HDL levels above 40 mg/dl (above 50 mg/dl for women), and triglycerides below 150 mg/dl. If all your levels fall in these low-risk categories, you and your doctor may decide that you only need to have a lipid profile done every two years. People with diabetes who have cholesterol levels out of the low-risk ranges may be given a repeat test to verify the results.
A child with diabetes older than two years should be tested at the time of diagnosis if there is a family history of high cholesterol or heart disease or if family history is unknown. If there is no family history of high cholesterol or heart disease, the child should be tested at puberty. Children 12 and older who are diagnosed with diabetes should have a lipid profile done at the time of diagnosis and again after blood glucose levels have been brought under control. Subsequent checks of children need only be done every two years if levels are acceptable.