Although the words “ breast cancer ” strike fear in the hearts of many women, it is in fact the heart—specifically heart disease—that is the number one killer of women in America. Heart disease is a large subgroup of cardiovascular diseases (CVDs), which also include conditions such as stroke and hypertension . CVDs kill twice as many women as all forms of cancer combined.

In recent years, studies have shown that middle-aged women who are at low risk for CVD are less likely to die of CVD as they age. The same has been shown for young and middle-aged men.

Now, in a study published in the October 6, 2004 Journal of the American Medical Association , researchers have extended these findings to young women. They showed that young women with few or no risk factors for CVD were less likely to die of CVD when they got older, compared to women who were at high risk in their youth.

About the Study

Between 1967 and 1973, scientists from the Chicago Heart Association (CHA) Detection Project in Industry Study enrolled 7,302 women ages 18–39 with no history of coronary heart disease and normal electrocardiograms (ECGs). They identified low risk factors and high risk factors as follows:

Low risk factors

  • Systolic blood pressure 120 millimeters of mercury (mm Hg) or lower
  • Diastolic blood pressure 80 mm Hg or lower
  • No antihypertensive medications
  • Serum cholesterol less than 200 milligrams per deciliter (mg/dL [5.2 mmol/L]) without cholesterol-lowering medications
  • Body mass index (BMI, a standard measure of weight relative to height) less than 25
  • No diabetes
  • Nonsmoker

High risk factors

  • Systolic blood pressure 140 mm Hg or higher
  • Diastolic blood pressure 90 mm Hg or higher, or taking antihypertensive medication
  • Serum cholesterol 240 mg/dL (6.2 mmol/L) or higher, or taking cholesterol-lowering medication
  • BMI of 30 or higher
  • Diabetes
  • Smoker

Two or more high risk factors

The researchers classified the participants into four groups, based on their risk for CVD:

  • Low risk: all low risk factors (1,469 women)
  • Unfavorable risk: one or more risk factors falling between high and low (1,558)
  • Moderately high risk: only one high risk factor (3,217)
  • High risk: two or more high risk factors (1,058)

They followed the participants for an average of 31 years, tracking the number of deaths due to coronary heart disease (CHD), CVD, and from all causes.

The Findings

During the 31 years of follow-up, 47 women died of CHD, 94 died of other types of cardiovascular disease, and 469 women died from all causes.

The researchers observed that women with unfavorable risk (only one high risk factor) at baseline were more than three times as likely to die of CVD than women at low risk. Women at high risk (two or more high risk factors) were about six times as likely to die of CVD as women at low risk.

The trend was similar for coronary heart disease death. Women with unfavorable risk were about 3 ½ times as likely to die of CHD as women with low risk, and women at high risk were at almost eight times the risk. The risk of death from any cause was also increased in women with one or more high risk factors compared to those at low or unfavorable risk.

The study findings were limited by the fact that risk factors were measured only once, at the beginning of the study.

How Does This Affect You?

This study demonstrates that young women who are at low risk for CVD are less likely to die of CVD or from any cause, as they get older. In this study, the risk profiles of women as young as 18 were predictive of their future risk of CVD death.

A healthy lifestyle plays a tremendously important role in reducing the cardiovascular disease risk factors identified in this study. These results make the case that girls and young women can expect to reap the benefits of these health behaviors many decades into the future. This is presumably because children who eat healthfully and exercise regularly are more likely to do so as young and older adults. And in doing so, they are more likely to hold off the degenerative diseases that await us as we age.