Daily consumption of 3 to 4 drinks of hard (distilled) liquor is associated with an increased risk of pancreatic cancer, even for those individuals who have never smoked, according to results from a massive prospective study published today in the Archives of Internal Medicine.
In 2009, a panel of experts convened by the International Agency for Research on Cancer concluded that the evidence of such a link was limited. But the new data from the Cancer Prevention Study II, a prospective study of more than 1 million individuals who were followed up for more than 20 years, bolster the evidence base by addressing some of the limitations of previous studies.
“One of the remaining concerns was teasing out the effects of smoking because drinkers are also often smokers,” explained Susan M. Gapstur, PhD, MPH, vice president of epidemiology research at the American Cancer Society (ACS) in Atlanta. “Because the Cancer Prevention Study II was such a large study, we were able to look at the risk of pancreatic cancer in those individuals who drank alcohol but were never smokers.”
Such an association with beer or wine drinking was not seen, but Gapstur cautioned that may have to do with the quantity of alcohol consumed per drink rather than the type of alcoholic beverage. “We didn’t ask how big a drink, just how many,” she said. “For beer, the amount of alcohol per drink is pretty standard and for wine there is also not a lot of variability. But with hard liquor, the amount of alcohol per drink varies.”
Although the study does not explain how heavy alcohol consumption might cause pancreatic cancer, some plausible mechanisms have been proposed. “Chronic heavy drinking increases the risk of pancreatitis and that has been linked to pancreatic cancer,” explained Gapstur. “There is also research that shows alcohol can be metabolized in the pancreas and some of the first metabolites can have effects on the cell that alter pathways involved in cancer.”
“These results continue to underscore the importance of following the ACS guidelines [on cancer prevention]: if you drink, limit your intake to no more than 1 drink per day for women and no more than 2 drinks per day for men,” Gapstur said.