People who drink two or more cups of coffee per day are 66 percent less likely to die from certain forms of liver disease, according to a study conducted by researchers with the Duke-NUS Graduate Medical School Singapore and the National University of Singapore and published in the journal Hepatology this month.
The study was funded by the U.S. National Institutes of Health.
"Our study is the first to demonstrate a difference between the effects of coffee on non-viral and viral hepatitis related cirrhosis mortality," lead researcher Dr. Woon-Puay Koh said.
Cirrhosis of the liver is a major health concern worldwide. In the United States, it is the 11th leading cause of death. In Europe, an estimated 29 million people suffer from chronic liver disease, and cirrhosis kills 17,000 annually. According to a 2004 report by the World Health Organization (WHO), liver cirrhosis is responsible for 1.3 percent of all deaths around the world.
Previous studies have suggested, however, that coffee consumption may reduce the risk of this disease. In order to further investigate this connection, researchers studied 63,275 people involved in the Singapore Chinese Health Study. The study consisted of Chinese people living in Singapore who were between the ages of 45 and 74, enrolled between 1993 and 1998 and were followed for an average of 15 years. At the study's starts, participants provided detailed information on their medical history, diet and lifestyle factors.
During the study followup period, 14,928 participants died, 114 of them from liver cirrhosis. The researchers found that the risk of death from cirrhosis was 66 percent lower among those who drank two or more cups of coffee per day than among those who drank no coffee at all.
This protection applied only to non-viral hepatitis-related cirrhosis, not to viral hepatitis-related mortality. The researchers believe that non-alcoholic fatty liver disease accounted for most of the non-viral deaths.
"This finding resolves the seemingly conflicting results on the effect of coffee in Western and Asian-based studies of death from liver cirrhosis," Dr. Koh said.
"Our finding suggests that while the benefit of coffee may be less apparent in the Asian population where chronic viral hepatitis B predominates currently, this is expected to change as the incidence of non-viral hepatitis related cirrhosis is expected to increase in these regions, accompanying the increasing affluence and westernizing lifestyles amongst their younger populations."
The study further confirmed the well known link between alcohol and liver disease: Those who consumed 20 g of alcohol (just over one drink) per day were significantly more likely to die from liver cirrhosis.
Coffee also protects against hepatitisThe study is only the latest to suggest liver-protecting benefits from coffee consumption. A study conducted by researchers from the National Cancer Institute and published in the journal Hepatology in 2009 found less severe symptoms among hepatitis C-related bridging fibrosis or cirrhosis patients who had not responded to standard treatments, but who did drink more coffee.
"Given the large number of people affected by HCV [hepatitis C virus] it is important to identify modifiable risk factors associated with the progression of liver disease," lead researcher Dr. Neal Freedman said. "Although we cannot rule out a possible role for other factors that go along with drinking coffee, results from our study suggest that patients with high coffee intake had a lower risk of disease progression."
Approximately 2.2 percent of the global population is infected with the hepatitis C virus, including more than 3 million people in the United States. The virus is the foremost cause of liver transplant in the United States, according to the Centers for Disease Control and Prevention, and causes between 8,000 and 10,000 deaths each year. It can lead to cirrhosis of the liver or liver cancer.
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