What do cholesterol numbers mean?

Your total blood cholesterol is a measure of the cholesterol components LDL (low density-lipoprotein) cholesterol, HDL (high-density lipoprotein) cholesterol, and VLDL (very low-density lipoprotein, which is the triglyceride-carrying component of lipids). Total cholesterol values cannot be interpreted in the absence of the cholesterol components listed below.

Kinds of cholesterol

LDL (low density-lipoprotein) cholesterol is also called bad cholesterol. LDL can build up on the walls of your arteries and increase your chances of getting heart disease. If you do not have heart or blood vessel disease and are not at high risk for developing heart disease, the following guidelines apply.

Your LDL cholesterol number is:

• Optimal if it is less than 2.6 mmol/L (100 mg/dL)
• Near optimal/above optimal if it is 2.6 3.3 mmol/L (100-129 mg/dL)
• Borderline high if it is 3.4 4.1 mmol/L (130-159 mg/dL)
• High if it is 4.14 4.9 mmol/L (160-189 mg/dL)
• Very high if it is 4.92 mmol/L (190 mg/dL) or above 

The treatment goal for individuals with heart disease or blood vessel disease is to reach an LDL of less than 1.8 mmol/L (70 mg/dL). The treatment goal for high-risk individuals (those with diabetes or other multiple risk factors for heart disease) is to reach an LDL of less than 2.6 mmol/L (100 mg/dL).

HDL (high-density lipoprotein) cholesterol is also called good cholesterol. HDL protects against heart disease by taking the bad cholesterol out of your blood and keeping it from building up in your arteries. Your HDL cholesterol number is:

• Low (and considered a risk factor) if it is less than 1 mmol/L (40 mg/dL)
• Good (and able to help lower your risk of heart disease) if it is 1.6 mmol/L (60 mg/dL) or more

Triglycerides are the chemical form in which most fat exists in food and the body. Triglycerides are mostly carried in VLDL and chylomicrons. VLDL comes from the liver and also has cholesterol. Chylomicrons come from dietary fat.

Along with cholesterol, triglycerides form plasma lipids. Excess triglycerides in plasma have been linked to the occurrence of coronary artery disease in some people. Like cholesterol, increases in triglyceride levels can be detected by plasma measurements. These measurements should be made after an overnight food and alcohol fast. Your triglyceride numbers are:

• Normal if they are less than 1.7 mmol/L (150 mg/dL)
• Borderline high if they are 1.7 2.25 mmol/L (150-199 mg/dL)
• High if they are 2.26 - 5.64 mmol/L (200-499 mg/dL)
• Very high if they are 5.65 mmol/L (500 mg/dL) or higher

Who should get a cholesterol screening?

Everyone over the age of 20 should get their cholesterol levels measured at least once every five years. The test that is performed is a blood test called a lipoprotein profile. That includes:

• Total cholesterol level
• HDL
• Triglycerides

LDL level is calculated from the above 3 values.

What affects cholesterol levels?

A variety of factors can affect your cholesterol levels. They include:

• Diet ” Saturated fat, trans fat, and cholesterol in the food you eat increase cholesterol levels. Try to reduce the amount of saturated fat, trans fat, and cholesterol in your diet. This will help lower your blood cholesterol level. Saturated fat and trans fat have the most impact on blood cholesterol.
• Weight ” In addition to being a risk factor for heart disease, being overweight can also increase your triglycerides. Losing weight may help lower your triglyceride levels and raise your HDL.
• Exercise ” Regular exercise can lower LDL cholesterol and raise HDL cholesterol. You should try to be physically active for 30 minutes on most days.
• Age and gender ” As we get older, cholesterol levels rise. Before menopause, women tend to have lower total cholesterol levels than men of the same age. After menopause, however, women's LDL levels tend to rise.
• Heredity ” Your genes partly determine how much cholesterol your body makes. High blood cholesterol can run in families.