Cirrhosis progressively destroys healthy liver tissue and replaces it with scar tissue. Viruses such as hepatitis C can cause cirrhosis, but long-term, heavy alcohol use is the most common cause of the disease in developed countries, according to background information in the article. Most alcohol drinkers, however, never develop cirrhosis; other factors that may play a role include genetics, diet and nutrition, smoking and the interaction of alcohol with other toxins that damage the liver.
Arthur L. Klatsky, M.D., and colleagues at the Kaiser Permanente Medical Care Program, Oakland, Calif., analyzed data from 125,580 individuals (55,247 men and 70,333 women) who did not report liver disease when they had baseline examinations, between 1978 and 1985. Participants filled out a questionnaire to provide information about how much alcohol, coffee and tea they drank per day during the past year. Some of the individuals also had their blood tested for levels of certain liver enzymes; the enzymes are released into the bloodstream when the liver is diseased or damaged.
By the end of 2001, 330 participants had been diagnosed with cirrhosis, including 199 with alcoholic cirrhosis. For each cup of coffee they drank per day, participants were 22 percent less likely to develop alcoholic cirrhosis. Drinking coffee was also associated with a slight reduction in risk for other types of cirrhosis. Among those who had their blood drawn, liver enzyme levels were higher among individuals who drank more alcohol, indicating liver disease or damage; however, those who drank both alcohol and coffee had lower levels than those who drank alcohol but did not drink coffee, with the strongest link among the heaviest drinkers.
Tea drinking was not related to reduced risk in the study, suggesting that it is not caffeine that is responsible for the relationship between coffee and reduced cirrhosis risk. "Previous reports are disparate with respect to whether the apparently protective coffee ingredient is caffeine; in our opinion this issue is quite unresolved," the authors write.
The findings do not suggest that physicians prescribe coffee to prevent alcoholic cirrhosis, the authors continue. "Even if coffee is protective, the primary approach to reduction of alcoholic cirrhosis is avoidance or cessation of heavy alcohol drinking," they conclude. "Assuming causality, the data do suggest that coffee intake may partly explain the variability of cirrhosis risk in alcohol consumers. Basic research about hepatic coffee-ethanol interactions is warranted, but we should keep in mind that coffee might represent only one of a number of potential cirrhosis risk modulators."
(Arch Intern Med. 2006;166:1190-1195. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This study was supported by a grant from the Kaiser Foundation Research Institute. Data collection from 1978 to 1985 was supported by a grant from the Alcoholic Beverage Medical Research Foundation, Baltimore, Md.