Habitual coffee drinking seems to be associated with a lower risk of developing liver cancer, according to a study conducted in Japan and reported in the Journal of the National Cancer Institute.

A second study in the same journal suggests that caffeinated coffee consumption is not tied to colorectal cancer, although decaffeinated coffee may decrease the risk of rectal cancer.

Dr. Manami Inoue and colleagues at the National Cancer Center in Tokyo surveyed approximately 90,000 individuals in 1990 or between 1993 and 1994. The subjects were followed through the end of 2001, during which time 334 were diagnosed with liver cancer.

The risk of liver cancer among those who almost never drank coffee was twice as high as for those who drank coffee on a daily basis.

The investigators observed no association between green tea intake and the risk of liver cancer, suggesting that antioxidants unique to coffee may be responsible for its protective effects.

In the second article, Dr. Karin B. Michels at Brigham and Women’s Hospital in Boston and colleagues analyzed data from 88,000 women in the Nurses’ Health Study, which began in 1976, and from 46,000 men in the Health Professionals’ Follow-up Study, which began in 1986. During followup through 1998, there were 1433 cases of colorectal cancer.

Total coffee or tea consumption was not associated with the development of colorectal cancer in either group.

However, among subjects who reported never drinking decaffeinated coffee, the occurrence of rectal cancer was 58% higher than among those who drank two or more cups per day.

While results were consistent for both cohorts, Dr. Michels’ group says the relationship of decaffeinated coffee to a lower risk of rectal cancer should be looked at again in additional studies.

SOURCE: Journal of the National Cancer Institute, February 16, 2005.