This is the VOA Special English Science Report.
Medical researchers say older women may be increasing their chances of developing the disease rheumatoid arthritis if they drink a lot of decaffeinated coffee. Caffeine is a substance naturally found in coffee. When caffeine is removed from coffee it is called decaffeinated coffee or "decaf."
Rheumatoid arthritis is a disease in which the body's defense system attacks the tissue surrounding the joints, the places where bones are joined. This causes swelling, pain and difficulty moving. The disease affects women more than men.
Researchers from the University of Alabama in Birmingham reported their study at the yearly meeting of the American College of Rheumatology in San Francisco, California. They studied more than thirty-one-thousand women between the ages of fifty-five and sixty-nine. The women were included in the Iowa Women's Health Study from Nineteen-Eighty-Six through Nineteen-Ninety-Seven.
The researchers studied one-hundred-fifty-eight women who developed rheumatoid arthritis during that period. They also studied women who did not develop the disease.
Women who drank four or more cups of decaffeinated coffee a day were two times more likely to develop rheumatoid arthritis than women who never drank decaf. The study also found that drinking tea decreased risk for the disease. The women who drank more than three cups of tea a day had a sixty percent lower chance of developing the disease than those who never drank tea. The researchers found that coffee with caffeine was not linked to the development of the disease.
Researchers from Boston University in Massachusetts reported about another study. It involved rheumatoid arthritis among sixty-four-thousand black women. The women were involved in the Black Women's Health Study that began in Nineteen-Ninety-Five. The researchers found that drinking more than one cup of decaffeinated coffee a day seemed to increase by four times the chance of developing the disease. However, in this study, drinking tea seemed to increase the chance of developing rheumatoid arthritis.
The researchers said they believe these are the first studies to show a link between decaf coffee and rheumatoid arthritis. But they said people should not stop drinking decaf or tea until more studies are done.
This VOA Special English Science Report was written by Nancy Steinbach.