(HealthScoutNews) -- Women with rheumatoid arthritis face a much greater risk of heart attacks than those without the disease, says a new study.
Between 1976 and 1996, researchers tracked more than 114,000 women, including 527 with rheumatoid arthritis (RA), and found that those with RA were twice as likely to have heart attacks as women without RA.
Women who had RA for at least 10 years faced three times the risk of heart attacks, says the study, which will appear in the March 11 issue of Circulation: Journal of the American Heart Association.
Researchers from the Brigham and Women's Hospital in Boston adjusted the figures to take into account known risk factors for heart attacks, such as age, smoking, hypertension, diabetes and high cholesterol.
Dr. Daniel H. Solomon, a clinical rheumatologist and assistant professor at Brigham and Women's Hospital, said the findings should influence treatment of patients with RA because of the greater likelihood of heart attacks.
"Patients with RA and their doctors should consider RA being a risk factor for heart attacks, and that should trigger people to test for and manage risk factors for heart disease among those with RA," Solomon said.
Brigham researchers plan further study to determine whether such steps as cholesterol-lowering treatment, blood-pressure medication and regular low doses of aspirin for RA patients may reduce the risk of heart attack.
The study did not establish conclusively reasons for the connection between RA and heart attacks.
Solomon, however, said other studies have linked RA and increased rates of heart disease because inflammation, common in arthritis, is believed to contribute to fatty build-up in the blood vessels, which can cause heart attacks.
Further research could help determine whether anti-inflammatory drugs for RA also reduce the risk of heart disease, Solomon said.
The study notes earlier research has found that many cells in the lining of inflamed joints also are found in atherosclerosis -- plaque deposits that eventually can block an artery and cause a heart attack or stroke. Other research also has shown common characteristics of RA and heart disease: abnormal T cells, which regulate inflammation, and elevated C-reactive protein, whose level increases with inflammation of blood vessels.
Rheumatoid arthritis affects 2.1 million Americans, about 1.5 million of them women, and causes inflammation in the lining of the joints. RA is an autoimmune disease in which the body's immune system attacks healthy joint tissue, causing inflammation and then joint damage.
Doctors treating RA often overlook possible links between RA and heart disease, Solomon said.
"Quite frankly, lots of people [with RA] have pain and disability," he added. "So the doctors are managing that pain and disability and perhaps not focusing on long-term issues like heart disease awareness and education."
The women the researchers tracked were among the 121,700 nurses enrolled in the Nurses' Health Study, started at Brigham and Women's Hospital in 1976. The nurses were 30 to 55 when the study began and have been sent questionnaires every two years to update medical and lifestyle information.
Researchers excluded from the study women who reported RA, cardiovascular disease or cancer in the initial 1976 questionnaire.
Dr. Elizabeth Ross, a cardiologist based in Washington, D.C., said the study shows that it appears RA increases the risk of heart attacks, but adds that the reason remains unclear.
"It's an interesting study; it certainly heightens our interest in inflammation," said Ross, a national spokeswoman for the American Heart Association.
"Maybe RA is one of those disorders where we need to be more aggressive in prevention of treatment of heart disease," she said.
But Ross said many factors contribute to heart attacks. "You have to consider there are a lot of unknowns, and this may not be a cause-and-effect" between RA and heart attacks. "There could be other factors," she said.
The study, she noted, did not measure C-reactive proteins, markers for inflammation, in the two groups, and did not explain a much higher proportion of women in the non-RA group who were premenopausal. Pre-menopausal women are less likely to suffer heart disease, she said.
Ross added that the study reinforces the need to focus on such known risk factors for heart disease as blood pressure, smoking, diet and exercise.
For more on rheumatoid arthritis, visit the Arthritis Foundation. To learn how anti-inflammatory drugs may reduce heart attack risk, try the American Heart Association.
SOURCES: Daniel H. Solomon, M.D., M.P.H., clinical rheumatologist, assistant professor, Brigham and Women's Hospital, Boston; Elizabeth Ross, M.D., cardiologist, Washington, D.C., and national spokeswoman, American Heart Association; March 11, 2003, Circulation: Journal of the American Heart Association~HATT~~ARTM~~RHAR~~WMEN~
For more information on heart attack prevention, visit our Heart Attack Center.