A recent study by Montreal researchers found a strong link between heavy alcohol consumption and six different types of cancer in men. But the researchers also found that while moderate wine consumption slightly elevated the risk of melanoma and rectal cancer, it lowered the risk of several other cancers. Beer and spirits appeared to be greater risk factors.
The research, conducted by Dr. Andrea Benedetti of McGill University in Montreal, Dr. Marie-Elise Parent of the Université du Québec and Dr. Jack Siemiatycki of the Université de Montréal, focused on the association between regular alcohol consumption over a lifetime and risk of cancer. The study is published in the current issue of the journal Cancer Detection and Prevention.
Numerous studies over the years have found links between alcohol consumption and cancer, but few have looked at consumption patterns and the specific types of alcohol consumed. In the study text, the Montreal scientists reported that given the widespread consumption of alcohol and the "different compositions and consumption patterns of beer, wine and spirits, it is important to investigate the specific roles of each of these types of beverages," and the risk of cancer.
The team gathered and analyzed data from a large study conducted in Montreal in the early 1980s. There were 3,571 participants in that study—all men aged 35 to 70—who provided detailed information on their alcohol consumption, as well as a host of factors such as smoking habits, diet and socioeconomic status. About 14 percent of the men were nondrinkers, about half drank weekly and 36 percent consumed alcohol daily.
In the new study, data on 13 types of cancer were examined: bladder, colon, esophagus, liver, lung, lymphoma (both Hodgkin's and non-Hodgkin's), kidney, melanoma, pancreas, prostate, rectal and stomach. The scientists then analyzed the data to see if there were noticeable trends surrounding daily alcohol consumption and the risk of these cancers.
The researchers classified the men in the study by how many drinks they consumed daily multiplied by how many years they drank. A man who drank four drinks a day for 25 years, for example, accumulated 100 "drink-years."
The research team found that regular heavy consumption of alcohol (classified as 180 drink-years or more) increased the risk of esophageal and liver cancer more than sevenfold. The risk of colon, stomach and prostate cancer was about 80 percent higher among heavy drinkers, while lung cancer risk rose by almost 60 percent, compared to nondrinkers. Heavy drinking posed no apparent excess risk for pancreatic cancer, rectal cancer, kidney cancer, bladder cancer, melanoma, Hodgkin's lymphoma and non-Hodgkin's lymphoma.
"For the most part we showed that light drinkers were less affected or not affected at all," said Benedetti. "It is people who drink every day or multiple times a day who are at risk. This adds to the growing body of evidence that heavy drinking is extremely unhealthy in so many ways."
In a secondary analysis that separated alcohol beverage by type, the results were less alarming for moderate wine drinkers. Those who drank between one to six glasses of wine per week showed an increased risk of rectal cancer and melanoma—7 percent and 9 percent, respectively.
For most of the other cancers, moderate wine drinkers showed a lower risk of the diseases, averaging 10 percent to 20 percent less, compared to non-drinkers. The moderate wine drinkers enjoyed a 41 percent lower risk of pancreatic cancer and a 35 percent lower risk for both forms of lymphoma.
"When we looked at alcohol-specific estimates, increased risks seemed to be driven by beer and/or spirits consumption," said Benedetti, who stopped short of speculating why wine drinkers may enjoy less risk of cancer. "Well, [it] could be a number of things," she said, such as, "that wine drinkers are different than beer and/or spirits drinkers, even though we saw the effect after adjusting for cigarette smoking, socioeconomic status, etc. Maybe there is something in wine that is 'good' for you. We weren't able to explore that in this work."