The following are confirmed independent risk factors for the development of CAD:
- Hypercholesterolemia (specifically, serum LDL concentrations)
- Smoking
- Hypertension (high systolic pressure seems to be most significant in this regard)
- Hyperglycemia (due to diabetes mellitus or otherwise)
- Type A Behavioural Patterns, TABP. Added in 1981 as an independent risk factor after a majority of research into the field discovered that TABP's were twice as likely to exhibit CAD than any other personality type.
- Hemostatic Factors: High levels of fibrinogen and coagulation factor VII are associated with an increased risk of CAD. Factor VII levels are higher in individuals with a high intake of dietary fat. Decreased fibrinolytic activity has been reported in patients with coronary atherosclerosis.
- Hereditary differences in such diverse aspects as lipoprotein structure and that of their associated receptors, homocysteine processing/metabolism, etc.
- High levels of Lp(a):
What is Lp(a)?
When LDL cholesterol combines with a substance known as Apoliprotein (a), the result is a compound known as Lp(a), or "ugly" cholesterol. Lp(a) is called ugly cholesterol because evidence from some research studies shows that in high levels, it can increase a person's risk of heart attack or stroke, even if cholesterol levels are otherwise "desirable." Lp(a) is measured through a blood sample and can be tested as part of a lipoprotein panel.
Genetics determines your levels of Lp(a) and even the size of the Lp(a) molecule itself. Lifestyle changes do not alter levels of Lp(a); instead, levels for most people tend to remain consistent over a lifetime except for women, who will experience a slight rise in levels with menopause. Some physicians request testing of Lp(a) for patients who have a strong family history of premature heart disease or hypercholesterolemia. It can be a valuable test, particularly when other types of cholesterol are at healthy levels, yet concern exists that heart disease is developing. Physicians will typically order this test if a patient has had a heart attack or stroke, yet cholesterol levels fall within a "healthy" category.
Berkeley Heart Lab, Inc., based in Burlingame, California, offers a number of advanced lipid tests-including a test for levels of Lp(a)-that provide quantitative determinations of lipoprotein subclasses. According to Jeffrey Aroy of Berkeley HeartLab, Inc., "the value of the quantitative measurements is that they go beyond simply noting whether levels are 'good' or 'bad.' Instead, these measurements not only provide guidance for therapeutic treatment, but also provide valuable insight into the success of therapy and the need for adjusting treatment approaches on an ongoing basis."
Approximately 50 percent of people who have heart attacks do not have elevated cholesterol levels. These individuals, however, typically have higher levels of CRP, Lp(a), Apo S, or homocysteine. As researchers continue to learn about the exact mechanisms of heart disease, more tests are developed to identify and measure these other risk factors and markers.
Treatment for elevated Lp(a) includes niacin therapy. Some experts believe that antioxidant
therapy is also useful. People with high levels of Lp(a) benefit by concentrating their efforts OR lowering LDL levels since at lower levels, it is harder for LDL particles to attach to plaque buildup. Lowering LDL levels ultimately lowers the level of risk.
According to a study published in the New England Journal of Medicine in November 2003, researchers found that elevated levels of Lp(a) among healthy men age sixty-five years and older are predictive of the risk of stroke and death. Study participants with the highest levels of Lp(a) were more likely to experience a stroke and were 76 percent more likely to die than men with the lowest levels. These researchers support the use of Lp(a) testing as a screening tool to measure the risk of stroke and heart disease in older men.
Significant, but indirect risk factors include:
- Lack of exercise
- Stress
- Diet rich in saturated fats
- Diet low in antioxidants
- Obesity
- Men over 60; Women over 65
Risk factors can be classified as
- Fixed: age, sex, family history
- Modifiable: smoking, hypertension, diabetes mellitus, obesity, etc.
Further Reading
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"Coronary artery disease"
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