The CHD (Coronary Heart Disease) risk calculation is based on a scoring system that grew out of the Framingham Heart Study. A person's risk (chance) of developing CHD in the next 10 years is calculated based on the cholesterol level as well as other non-cholesterol risk factors. The non-cholesterol risk factors are classified as highest risk factors, major risk factors, and other risk factors.
The following classification is modified from the new
NCEP guidelines published in the Journal of the American Medical Association (JAMA) (2001).
The highest risk factors include:
- Having already developed CHD, as evidenced by a prior heart attack, bypass surgery, etc.
- Having already developed arteriosclerosis (hardening and narrowing) in arteries other than the heart. Arteriosclerosis in the other arteries can lead to poor circulation in the lower extremities, aneurysm of the abdominal aorta.
The major risk factors include:
- Men over 45 years and women over 55 years
- High blood pressure (BP >140/90 mmHg or taking high blood pressure medications)
- HDL cholesterol <40mg/dl
- Having first-degree male relatives with CHD (such as a heart attack) before age 55 years and first-degree female relatives with CHD before age 65 years.
Individuals with any one of the highest risk factors have the highest
CHD risk. More than 20 out of 100 in this group might develop CHD or a recurrent
CHD event such as a heart attack within 10 years (i.e., they have a 10-year CHD
risk of >20%).
Individuals with 0-1 major risk factors usually have 10-year CHD risk of <10%.
Individuals with 2 or more of the major risk factors can have 10-year CHD risks of <10%, 10%-20%, or >20%.
Other risk factors include high saturated fat and high cholesterol diet, sedentary lifestyle, and elevated homocysteine and lipoprotein(a) levels. Even though these risk factors were not used in the Framingham risk score calculation, they are recognized risk factors for CHD.