Men who down more than four alcoholic drinks in a day may have a heightened risk of stomach cancer, a large European analysis suggests.
A number of studies have looked at whether people's drinking habits are related to their risk of stomach cancer, and come to mixed conclusions.
These latest findings, from a study of more than 500,000 European adults, suggest that heavy-drinking men are more likely to develop the cancer than light drinkers are.
At the start of the study, 10,000-plus men said they averaged more than four drinks per day. And their odds of developing stomach cancer over the next decade were twice those of light drinkers (who had the equivalent of about half a drink per day or less).
When the researchers looked more closely at the type of alcohol people consumed, they found that beer, in particular -- as opposed to wine or liquor -- seemed to be connected to stomach cancer risk.
There were no similar connections seen in women, according to the researchers, led by Dr. Eric J. Duell of the Catalan Institute of Oncology in Barcelona, Spain. But there were also far fewer heavy drinkers among the female participants (just under 2,300).
The findings, reported in the American Journal of Clinical Nutrition, do not prove that alcohol itself leads to stomach cancer in some men.
And the absolute risk for any one heavy drinker may be small. Of nearly 13,000 men and women who were heavy drinkers when they entered the study, just 33 developed stomach cancer over the follow-up period.
Still, experts already recommend that people who drink do so only in moderation. That generally means no more than two drinks per day for men, and no more than one for women.
Heavy drinking is linked to cancers of the mouth and throat, as well as other serious conditions like scarring of the liver.
Stomach cancer is relatively uncommon in the US and other Western countries, though it's much more prevalent in other parts of the world, particularly developing nations. About 21,500 Americans will be diagnosed with stomach cancer this year, according to the American Cancer Society.
Smoking is one of the risk factors for the disease. And in some past studies, it's been hard to separate the possible effects of heavy drinking on stomach cancer from those of smoking -- since the same people often have both habits.
In the current study, though, Duell's team found that heavy drinking was linked to stomach cancer in men regardless of smoking habits.
The link also held when the researchers factored in people's diet habits (red and processed meats, for example, have been tied to stomach cancer) and any infection with H. pylori -- a type of bacteria that contributes to ulcers.
While most people with H. pylori do not develop cancer, persistent infection is thought to raise the risk of stomach cancer in certain people.
If heavy drinking is a cause of stomach cancer, it may be related to one of the metabolic byproducts of alcohol -- called acetaldehyde. The substance is a known human carcinogen, Duell's team notes.
On top of that, beer contains compounds known as nitrosamines, which cause cancer in animals. So it's possible, the researchers speculate, that the combination of those substances and acetaldehyde could explain why beer, in particular, was tied to stomach cancer in this study.