Every minute another person dies from coronary heart disease (CHD) in the U.S. In fact, more Americans die from CHD than any other disease or illness, and an estimated 13 million of us will develop CHD this year.

A number of factors can put you at increased risk of developing CHD, including smoking, obesity , sedentary lifestyle, diabetes , high cholesterol , high blood pressure , being male, being older than 50, and having a family history of heart disease. Although health professionals agree that these factors increase the risk of CHD, some question whether exposure to one or more of these risk factors will actually cause CHD. Recently, some researchers have suggested that more than half of people who develop CHD do not have any of the four major risk factors—high cholesterol, high blood pressure, smoking, and diabetes.

Two studies in the August 20, 2003 issue of the Journal of the American Medical Association looked at the prevalence of these risk factors in people with CHD. Both studies found that more than 80% of people with CHD have at least one major risk factor.

About the Study

The first study examined the exposure to high cholesterol levels, exposure to high blood pressure, smoking status, and history of diabetes treatment in 386,815 men and women between the ages of 18 and 59 who were participating in one three large trials—the Chicago Heart Association Detection Project in Industry (CHA), the Multiple Risk Factor Intervention Trial (MRFIT), and the Framingham Heart Study (FHS).

Follow-up for these studies lasted from 21–30 years, during which the researchers tracked how many people died from CHD. The researchers also tracked the number of people in the FHS who had a non-fatal heart attack . From these data, the researchers calculated the percentage of the people with CHD who were exposed to at least one of the following risk factors:

  • Total cholesterol of 240 milligrams per deciliter (mg/dL [6.2 mmol/L]) or higher
  • Diastolic blood pressure of 90 millimeters of mercury (mm Hg) or higher, or systolic blood pressure of 140 mm Hg or higher
  • Current use of blood pressure lowering medications or cholesterol lowering medications
  • Current cigarette use
  • Diagnosis of diabetes

The results were analyzed separately for men and women, and for younger (18–39 years old) and older (40–59 years old) people.

The second study was similar. In 2002 and 2003, researchers looked at 122,458 men and women from 14 international randomized trials that had taken place during the prior decade. These participants were enrolled in the study because they had:

  • Experienced an ST-elevation heart attack (a heart attack in which an artery leading to the heart is blocked and the heart muscle is extensively damaged)
  • Experienced unstable angina (chest pain) or a non-ST elevation heart attack (an artery is only partially blocked and damage is less extensive)
  • Undergone coronary artery opening procedures such as balloon angioplasty

Physicians interviewed the participants to find out whether they smoked, had high blood pressure, high cholesterol levels, and/or diabetes. The researchers calculated the percentage of participants who had one or more of the risk factors. The results were analyzed separately for men and women, and by age.

The Findings

The first study found that 87%–100% of the people who died from CHD had at least one major risk factor. Among the people who had a non-fatal heart attack, 92% of the men ages 40–59, and 87% of the women in the same age group had at least one major risk factor.

In the second study, at least one of the four major risk factors was present in 85%–90% of people with premature CHD (CHD in men 55 and younger or women 65 and younger). Overall, 85% of women and 81% of men with CHD reported having at least one risk factor.

How Does This Affect You?

Both of these studies challenge the myth that less than 50% of people who have CHD have major risk factors. These results suggest that, to fight the heart disease epidemic in America, more attention must be paid to lowering high blood pressure and cholesterol levels, quitting smoking, managing diabetes, and achieving a healthy weight (protective against high blood pressure and cholesterol, and diabetes).

Do these studies mean that physicians should begin more aggressively treating risk factors? It’s hard to say. While better control of these risk factors would likely decrease the prevalence of CHD, not everyone with a risk factor will develop CHD, and aggressive treatments are expensive and not without their risks.

These results clearly imply, however, that it is important for individuals to make lifestyle changes to decrease their risk for CHD. There are some risk factors you can’t control (your gender, age, and genetics), and there are some you can change (smoking, weight, diet, exercise). To reduce your risk for CHD, the Journal of the American Medical Association suggests you do the following:

  • Stop smoking.
  • Eat a low-fat diet rich in vegetables and fruits .
  • Maintain a healthy weight .
  • Exercise daily for at least 30 minutes.
  • Control diabetes and high blood pressure if you already have these problems.
  • Manage your cholesterol and blood lipid (fat) levels if they are elevated.
  • Know your family history, especially about heart attacks or sudden death before the age of 50.

You should visit your doctor regularly to monitor your health and get advice about how to manage risk factors, illnesses, or diseases you may already have.