Risk Factors for Coronary Artery Disease (Part 1)

By:  Samuel J. Stagg III, M.D., F.A.C.C., F.A.C.P.

Approximately one out of two of us will die of heart disease or stroke. Finding out which factors cause these diseases is crucial to prevention, diagnosis, and treatment of our most serious health risk.1

In the early 1960s, the initial results from the Framingham Heart Study2gave us an initial glimpse into the factors that contribute to coronary artery disease. The study began in 1948, studying the epidemiology of cardiovascular disease in Framingham, Massachusetts. It is currently on its third generation of participants.

The initial findings of this study show these factors as contributors to heart disease:

  1. Cigarette smoking
  2. Increased cholesterol
  3. Elevated blood pressure
  4. Obesity
  5. Lack of exercise

The latest update on risk factors for coronary artery disease was by the American College of Cardiology and American Heart Association in November 2013.3 The factors had been refined and expanded, and an understanding of these individual factors will help each of us evaluate our own personal risk of developing heart disease. The current risk factors for coronary artery disease are broken down into several categories.1 There are conventional/novel and non-modifiable/modifiable risk factors. I will spend the rest of the first article discussing the conventional risk factors, and these are the ones we are all more familiar with.

CONVENTIONAL RISK FACTORS

Non-modifiable Risk Factors (cannot do anything about)

  1. Older age – greater than 45 in men, greater than 50 in women.
  2. Family history – of early heart disease.
  3. Race – African-Americans as well as specific Asian-American populations have a higher risk.
  4. Gender – Men have a higher risk than women.

Modifiable Risk Factors (can do something about)

  1. High LDL cholesterol
  2. High blood pressure
  3. Cigarette smoking
  4. Diabetes mellitus
  5. Obesity
  6. Lack of exercise
  7. Metabolic syndrome
  8. Mental stress and depression

NON-MODIFIABLE RISK FACTORS

  1. Age – The older you are, the higher the risk. Women develop heart disease on average ten years later than men secondary to the protective effects of estrogen pre-menopausal. After menopause the cardiovascular risk of men and women is the same.
  1. Family history – I always tell patients, “You can’t pick your parents.” It is important to realize that if your parents or first-degree relatives have premature heart disease, then you are much more likely to have the same.
  1. Race – African-Americans have a higher risk than Caucasians, and Asians with low levels of high-density lipoprotein also have a significantly higher risk.
  1. Gender – The male sex carries a higher risk; however, at menopause the risk evens out. As mentioned, women develop coronary artery disease on average ten years later than men secondary to the protective effects of estrogen pre-menopausal.

You cannot do anything about the above factors, but it is crucially important to be aware of them and whether or not you have any of them. Each of these significantly raises your individual risk of coronary artery disease.

MODIFIABLE RISK FACTORS

We have individual control over these factors. Personal responsibility and awareness, diagnosis, and then treatment are paramount in heart health.

1. Abnormal blood cholesterol – High levels of LDL (low-density lipoprotein) are especially important in the development and progression of atherosclerosis.       LDL goals are in flux at this time, but my view is people with zero other risk factors should have an LDL less than 130. If you have one or more risk factors, then a goal of less than 100 is wise. If you have diabetes or known coronary artery disease or cerebrovascular disease, then a goal of less than 70 is ideal. Currently as well, anyone who has had a cardiovascular event or significant coronary artery disease should be treated with aggressive statin therapy whatever his LDL level is. People with heart attacks or strokes or known coronary disease even with apparently low LDL cholesterol levels should have aggressive medical management, ideally with moderate- to high-dose statin therapy.  In the same light, high-density lipoprotein or HDL is important, and a goal of greater than 40 in men and greater than 50 in women is recommended

2. High blood pressure – People do not feel hypertension usually, and that is why it is called the “silent killer”. Everyone needs to know his own blood pressure and have it checked periodically. Hypertension is a major risk factor for heart disease and stroke. There have been recent changes in the recommended blood pressure goals. The current recommendations are that blood pressure should be less than 140/90 in people less than 60 and less than 150/90 in people 60 or over.

3. Cigarette smoking – This is the single most important risk factor, in my opinion, in developing cardiovascular disease. In fact, cessation of cigarette smoking constitutes the single most important preventative measure for coronary artery disease.       The more you smoke the worse the risk, but even one to two cigarettes a day significantly increase your risk of coronary artery disease.

4. Diabetes mellitus – Seven percent of the U.S. population has diabetes.       Diabetics have two to eight times the risk of cardiovascular events than non-diabetics. This is a major risk factor that causes blockages in blood vessels in every area of the body. It increases the risk of coronary artery disease and heart attacks, cerebrovascular disease and strokes, peripheral vascular disease and claudication and ultimately gangrenous changes and amputations of the toes, feet, and even legs. Diabetes is epidemic in the United States with rising obesity and dietary indiscretion.

5. Obesity – This is causative in heart disease, diabetes, and hypertension and is also a cause and a result of lack of exercise—“the couch potato syndrome”.

6. Lack of physical activity – Maintaining good cardiovascular fitness is key in maintaining proper weight, blood pressure, blood sugar, and cardiac health.   It is important in both prevention and treatment of cardiovascular disease.       Cardiac rehabilitation and exercise is very important for people who have had heart attacks or bypass surgery. I recommend thirty minutes of cardiovascular exercise five days a week for ideal heart health.

7. Metabolic syndrome – People with metabolic syndrome have three of the following five traits:

  • Elevated waist circumference—40 inches or more in men, 35 inches or more in women
  • Elevated triglycerides – greater than 150 mg/dL or taking medications for elevated triglycerides
  • Low levels of HDL – less than 40 in men and less than 50 in women
  • Elevated blood pressure
  • Elevated fasting blood glucose which is 100 mg/dL or higher

High consumption of simple sugars and carbohydrates increases cardiovascular risk through metabolic syndrome, obesity, and diabetes.  

8. Mental stress and depression – Depression has been implicated in predicting coronary artery disease.4 There are multiple physiologic changes that occur with stress and depression, causing a negative cardiac impact.5

All of these factors, both non-modifiable and modifiable, cause heart disease. We should all be aware of which ones of these we have and realize they increase our risk of having a heart problem and even dying.

Of most importance are the factors we can do something about, i.e. the modifiable ones. We should all know our blood pressure, serum glucose, and LDL and HDL cholesterol levels. We should control our weight and especially control our portion sizes of sugars and carbohydrates. We should exercise five times a week for thirty minutes. Above all else, we should not smoke and if we do, Quit! Quit! Quit!

 

BIBLIOGRAPHY

  1. Boudi et al., Risk Factors for Coronary Artery Disease – Medscape Reference. Medscape.com/article/164163-overview.
  2. Mahmood, Ledy, Vasan, Wang, (2013) “Framingham Heart Study and the epidemiology of cardiac vascular disease: a historical perspective” Lancet 27:61752-3.
  3. Goff et al., (2013):ACC/AHA Guidelines on the Assessment of Cardiovascular Risk: A Report of the ACC/AHA Task Force on Practice Guidelines. Circulation. November 12, 2013.
  4. Rugulies R., Depression as a predictor for coronary heart disease – a review and meta-analysis. American Journal of Preventive Medicine. July 2002; 23(1):5161.
  5. Ghiadoni L, et al. Mental stress induces transient endothelial dysfunction in humans. Circulation. 102(20):2473-8.