The opposite may be true for black women, new research has found.
The study says black women who work outside of the home are less likely to have a heart attack than black homemakers.
The same connection between employment and protection against heart attacks wasn't found among white women, however.
Researchers aren't exactly sure why this is, but it's possible that black women benefit even more from employment than white women because black women tend to start out poorer, says April Perry, lead investigator on the study and a doctoral candidate at the University of North Carolina at Chapel Hill.
Better finances from working could give black women greater access to medical care. Black women who work might also have greater social support than black women who stay at home. Previous research has shown strong social relationships can help ward off heart disease.
The study was presented March 6 at the American Heart Association's annual conference on cardiovascular disease epidemiology and prevention in Miami.
Perry and her colleagues analyzed health and employment information of 6,855 women aged 45 to 64 taking part in a study of 16,000 middle-aged people called Atherosclerosis Risk in Communities. About 26 percent of the women were homemakers and 74 percent had jobs at the time.
During the next 11 years, 302 women had a "coronary event," including fatal and nonfatal heart attacks and surgical procedures to clear blockages in the heart.
After adjusting for age and socioeconomic status, researchers found that black homemakers were twice as likely as employed women to have a coronary event. There was no statistically significant difference among white homemakers or workers.
One of the reasons for the difference is that black homemakers had more physical risk factors for heart disease than black women with jobs. Black homemakers had higher rates of hypertension and diabetes, higher body mass indexes, higher cholesterol, and were more likely to smoke and drink alcohol, known risk factors for heart disease.
Even after controlling for those factors, black working women still had a 33 percent less risk of a coronary event than black homemakers. While the difference was not statistically significant from a research perspective, Perry says is still bears a closer look.
"More studies are needed looking at the employment situation of women, and physicians need to make sure that there is monitoring of the risk factors among these homemaking women," Perry says.
Richard A. Stein, a professor of clinical medicine at Cornell Medical Center and chief of cardiology at Brooklyn Hospital Center, both in New York, calls the study results "intriguing."
However, Stein, an American Heart Association spokesman, says discussing the reasons why is "pure speculation." Black women with jobs might get more exercise than homemakers. Employed women might have more money to buy healthier foods."
"All I can say is that concerns that African-American women in the workplace are going to have a higher incidence of heart disease because of the demands of juggling the responsibilities of home and job are not borne out by this study," he says.
Perry acknowledges that one weakness of the research is that the employment information was limited to whether or not the women were working at the time of the study. It's unknown if their employment status changed during the 11 years they were followed.
Women are expected to make up just under half of the U.S. labor force by 2010, Perry says.
"These findings should encourage additional research into the labor force experience of women and how these experiences may affect their cardiovascular health," Perry says.