NEW YORK (Reuters Health) - Data from 10 studies conducted in Europe and Japan suggest that people who drink coffee may be reducing their risk of liver cancer, although the reasons for the apparent protective effect of coffee remain to be determined.

The 10 studies reviewed by Dr. Francesca Bravi from Milan's Istituto di Ricerche Farmacologiche "Mario Negri" and colleagues included 2,260 cases of HCC. Collectively, the results showed a 41 percent reduction in the risk of liver cancer (or hepatocellular carcinoma, HCC) among coffee drinkers compared to those who never drank coffee.

Low to moderate coffee drinkers -- defined in some studies as those who drank less than 3 cups per day and in others as less than 1 cup per day -- had a 30 percent lower risk of HCC compared to coffee abstainers. High coffee consumption -- defined in some studies as 3 cups or more each day and in others as 1 cup or more per day - had a 55 percent lower risk of HCC.

"Moreover, the apparent favorable effect of coffee drinking was found both in studies from southern Europe, where coffee is widely consumed, and from Japan, where coffee consumption is less frequent, and in subjects with chronic liver diseases," the researchers note in their report in the medical journal Hepatology.

Animal and laboratory studies have suggested that certain compounds in coffee may block harmful enzymes involved in the development of cancer. Coffee drinking has also been linked to a lower risk of cirrhosis of the liver and chronic liver disease, which are the major risk factors for HCC. "Thus, there seems to be a continuum of the favorable effect of coffee on liver enzymes, cirrhosis, and HCC," note the authors.

Liver cancer is the third leading cause of cancer deaths in the world after lung and stomach cancer, with about 600,000 deaths in 2002.

Although a cause-and-effect relationship between coffee and liver cancer can not be determined based on the data, the current analysis provides "quantitative evidence" of a protective effect of coffee drinking on liver cancer, Bravi and colleagues write.

As reported by Reuters Health earlier this month, Japanese researchers recently found that drinking three or more cups of coffee a day may cut the risk of colon cancer in women by half.

SOURCE: Hepatology, August 2007.