TUESDAY, Dec. 11, 2012 (HealthDay News) -- People who drink more than four cups of caffeinated coffee daily could significantly reduce their risk of death from certain forms of cancer, according to a new study from the American Cancer Society.
Habitual coffee drinkers had about half the risk of dying from cancers of the mouth and pharynx (part of the throat) than others who never drank coffee or only had it occasionally, the researchers found.
"Coffee is one of the most widely consumed beverages in the world, and contains a variety of antioxidants, polyphenols, and other biologically active compounds that may help to protect against development or progression of cancers," the study's lead author, Janet Hildebrand, said in a society news release. "Although it is less common in the United States, oral/pharyngeal cancer is among the 10 most common cancers in the world. Our finding strengthens the evidence of a possible protective effect of caffeinated coffee in the etiology and/or progression of cancers of the mouth and pharynx."
In conducting the study, the researchers analyzed data on almost a million people from an American Cancer Society study on cancer prevention that began in 1982. Specifically, they examined the link between drinking caffeinated coffee, decaf, or tea with deadly forms of oral cancer.
The participants did not have cancer when the study began. Over the course of 26 years, however, 868 of them died of cancer of the mouth and pharynx.
The study found that drinking more than four cups of caffeinated coffee daily was linked to a 49 percent lower risk of death from oral cancer. Regardless of sex or whether or not the participants smoked or drank alcohol, the researchers pointed out that with each cup of coffee they consumed, their risk of death from this form of cancer dropped.
The study also suggests that drinking more than two cups of decaf coffee per day may have a similar benefit, but this finding only reached marginal statistical significance. No link was found between oral cancer and tea, they added.
The study authors noted that more research is needed to understand the reasons why coffee has a protective effect against oral cancers.
Two cancer experts said the study, while heartening for coffee drinkers, did have some drawbacks.
"Additional studies are necessary to confirm this effect and that it applies overall to the general population," said Dr. Robert Kelsch, of the division of oral pathology at North Shore-LIJ Health System in New Hyde Park, N.Y. He added that many of these oral and throat cancers have been tied to infection with the human papillomavirus (HPV), and the study "does not address any effect on HPV-related oral cancers."
In addition, Kelsch said, "keep in mind, this study only addresses possible reduced death from oral cancers. It does not suggest that caffeinated coffee will prevent whether you get oral cancer in the first place."
Dr. Marshall Posner is director of head and neck medical oncology at Mount Sinai School of Medicine in New York City. He said that "this is a provocative study and good news if you drink a lot of coffee."
However, Posner agreed that the role of HPV-linked cancer needs to be addressed. "Patients with HPV-related oropharynx cancer are cured in more than 75 percent of the cases, hence they did not show up in this study since their mortality from cancer is low," he explained.
"The study [also] does not address the risk of cancer development and coffee, which is a direct biologic question," Posner said, "and there are many behavioral factors among coffee drinkers and non-drinkers that might lead to lesser survival from oral/oropharynx cancer among subjects who did not drink coffee regularly."
Still, he added, "I will continue to drink coffee as opposed to tea, reassured by this work."
The study was published online Dec. 9 in the American Journal of Epidemiology. While the study found an association between coffee drinking and a lower risk of death from mouth and throat cancer, it could not prove cause-and-effect.
The U.S. National Library of Medicine has more about caffeine.