Women who drink a few cups of coffee and tea each day may have a lower risk of endometrial cancer, new study findings suggest.
Endometrial cancer arises in the lining of the uterus. Some risk factors have been established — including older age, obesity and factors that expose women to more estrogen, such as late menopause and estrogen therapy after menopause.
The possible role of diet has been less clear.
In the new study, researchers found that among nearly 1,100 women they surveyed, coffee and tea drinkers seemed to have a lower risk of the uterine cancer than non-drinkers.
Women who drank more than four cups of coffee and tea each day were only half as likely as non-drinkers to have endometrial cancer. Similarly, women who drank only tea — more than two cups per day — had a 44 percent lower risk of the disease.
Women who drank coffee alone showed a lower risk as well, but the evidence was not as strong. Those who drank more than two cups a day were 29 percent less likely to have endometrial cancer, but the finding was not significant in statistical terms, the researchers report in the International Journal of Cancer.
Exactly why tea and coffee might protect against endometrial is not certain. One possibility is caffeine, according to the researchers, led by Dr. Susan E. McCann of the Roswell Park Cancer Institute in Buffalo, New York.
When they looked only at decaffeinated coffee, the researchers found no link between the beverage and the risk of endometrial cancer.
In addition, they note, lab research shows that caffeine induces certain enzymes that help neutralize potentially cancer-causing substances in the body.
However, other compounds in tea and coffee may also be at work, according to McCann's team. Both beverages contain various antioxidant compounds — like flavonoids, catechins and isoflavones — which help protect body cells from damage that can eventually lead to cancer.
Still, the current findings show only an association between coffee and tea and lower endometrial cancer risk. The question of whether the beverages are responsible for the benefit requires further research.
McCann and her colleagues point out that in this study, at least part of the benefit seemed to be explained by coffee and tea drinkers' lower average weight.
SOURCE: International Journal of Cancer, April 1, 2009.