Coffee healthy living Coffee is associated with reducing the risk of brain tumor

NEW YORK (Reuters Health)-Coffee and tea drinkers have a reduced risk of developing the most common form of malignant brain tumor in adults, a new study shows.

The findings, based on a study of 500,000 adults in Europe, add to evidence from a recent U.S. study that coffee and tea drinkers have a reduced risk of brain gliomas. Glioma is a generic term for many brain tumors, accounting for 80% of adult malignant brain tumors.

"This is a preliminary study," said Dominica Michaud of Providence University in Rhode Island and Royal College London, who led the team."This study should not be a reason for anyone to change their coffee and tea intake."

Even if coffee and tea had some direct effect on reducing the risk of glioma, the effect was small. Overall, brain tumors are uncommon, with annual rates estimated at 4 - 6 per 100,000 women and 6 - 8 per 100,000 men in Europe, for example.

Overall, a person's lifetime chance of developing a malignant brain tumor (cancer) is less than one percent.

If high coffee and tea intake somehow protects against glioma, Michaud said, researchers could delve deeper into the causes of brain tumors. "Right now, we know very little about what causes brain cancer," she said in an interview.

The findings, published in the American Journal of Clinical Nutrition, are based on an ongoing survey of potential risk factors for cancer in ten European countries. At the start of the survey, 521,488 respondents aged 25 to 70 completed questionnaires about their medical history, diet, exercise habits, smoking and other lifestyle factors.

Michaud's team looked at more than 410,000 participants who were cancer-free at the time of the survey and had complete dietary information. After an average of 8.5 years of follow-up, 343 people were diagnosed with gliomas and another 245 with benign brain tumors called meningiomas.

When the researchers divided participants into four or five groups based on coffee and tea intake at the time of the survey, they found no "positive correlation with intake," meaning that increased coffee and tea intake was associated with a reduced risk of glioma.

But when the researchers looked at two groups: those who drank at least 3.5 ounces of coffee or tea a day, and those who drank less than 3.5 ounces a day or none at all.

Those who drank more coffee/tea had a one-third lower risk of being diagnosed with glioma, after taking into account factors such as age and smoking history. But there was no direct link with meningioma risk.

According to Michaud, they don't know why coffee and tea intake isn't positively associated with a reduced risk of glioma, which is often considered an important sign of a possible causal relationship. But this may have something to do with the difficulty of accurately measuring coffee and tea intake among participants, since the survey was based entirely on data reported by participants themselves.

Still, the finding that coffee/tea may affect glioma risk is biologically significant, Michaud said.

For example, a recent laboratory study found that caffeine slows the growth of glioblastoma. In addition, coffee and tea contain antioxidants that protect the body's cells from damage, thereby preventing cancer and other diseases.