Epidemiology

Coffee consumption may reduce risk of liver cancer

Last Updated: 2005-02-15 16:00:17 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Habitual coffee drinking may be associated with reduced risk of hepatocellular carcinoma (HCC), according to results of a prospective, population-based cohort study in Japan reported in the February 16th issue of the Journal of the National Cancer Institute.

A second study in the same journal suggests that caffeinated coffee consumption is not associated with the risk of 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 subjects in 1990 or between 1993 and 1994. Subjects were followed through the end of 2001, during which time 334 were diagnosed with HCC.

The risk of liver cancer among those who almost never drank coffee was 547.2 cases per 100,000 over 10 years. In comparison, the risk was 214.6 cases per 100,000 among those who drank coffee on a daily basis. The risk was inversely proportional to coffee intake (p for trend < 0.001).

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

In the second paper, Dr. Karin B. Michels at Brigham and Women's Hospital in Boston and colleagues analyzed data from the Nurses' Health Study (n = 87,794 women), which began in 1976, and from the Health Professionals' Follow-up Study (n = 46,099 men), 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 incidence of colorectal cancer in either group.

However, among subjects who reported never drinking decaffeinated coffee, the incidence of rectal cancer was 19 cases per 100,000 person-years of follow-up. Among those who drank two or more cups per day the incidence rate was 12 per 100,000. Results were consistent across both cohorts, the authors note.

Dr. Michels' group suggests that the inverse relationship between rectal cancer and the consumption of decaffeinated coffee should be confirmed in additional studies.

J Natl Cancer Inst 2005;97:282-300.