A separate study reported in the same issue of the journal reported no relationship between drinking caffeinated coffee or tea and the rates of colon or rectal cancer.
However, that analysis did find a 52 percent decline in rectal cancer among people who regularly drank two or more cups of decaffeinated coffee.
In that study a team led by Karin B. Michels of Brigham and Women's Hospital in Boston analyzed data from two large studies - the Nurses' Health Study of women and the Health Professionals' Follow-up Study involving men. The analysis of nearly 2 million person-years found 1,438 cases of colorectal cancer.
While they did not find any association between cancer rates and consumption of caffeinated coffee or tea, people who regularly drank two or more cups per day of decaffeinated coffee had about half the incidence of rectal cancer as those who never drank decaf.
The rate of rectal cancer was 12 cases per 100,000 person-years among those who consumed two or more cups of decaffeinated coffee per day. For those who never drank decaffeinated coffee, the rate was 19 cases per 100,000 person-years.
That difference may, however, be due to differences in lifestyle, the researchers commented, suggesting that drinkers of decaffeinated coffee might be more health-conscious overall.
The Japanese study was funded by the Ministry of Health, Labor and Welfare of Japan. The U.S. study was funded by the National Institutes of Health.
On the Net:
Journal of the National Cancer Institute:http://jncicancerspectrum.oupjournals.org/