"Our estimation of a cigarette equivalent for alcohol provides a useful measure for communicating possible cancer risks that exploits successful historical messaging on smoking," lead study author Dr. Theresa Hydes, of the Department of Gastroenterology and Hepatology at the University Hospital Southampton NHS Foundation Trust, said in a statement. "We hope that by using cigarettes as the comparator we could communicate this message more effectively to help individuals make more informed lifestyle choices." [7 Ways Alcohol Affects Your Health]

Dr. Richard Saitz, an addiction medicine specialist and chair of the Department of Community Health Sciences at Boston University School of Public Health, said that the study's comparison makes sense.

"I think it's about time that we communicate the cancer risks of alcohol — it's really been under the radar [and] this way is a good way to do it," said Saitz, who wasn't involved with the study.

Still, the researchers stress that the study isn't saying that moderate alcohol consumption is the same thing as smoking. The study only considered cancer risk, and not the risks of other health conditions, such as heart disease. In addition, the study looked at the lifetime risk of cancer in the general population, which might differ from an individual's cancer risk from either smoking or alcohol, the authors said.

Alcohol vs. cigarettes

To put alcohol's cancer risks in perspective, the study aimed to answer the question: In terms of cancer risk, how many cigarettes are in a bottle of wine? One bottle contains about 80 grams (2.5 ounces) of pure alcohol.

The researchers used national data from the U.K. on the lifetime risk of cancer in the general population as well as previously published research on the relationship between alcohol, smoking and cancer.

They estimated that, among nonsmokers, drinking one bottle of wine per week is tied to a 1.0 percent increase in lifetime cancer risk for men; and a 1.4 percent increase in lifetime cancer risk for women. In other words, if 1,000 men and 1,000 women each drank one bottle of wine per week, about 10 extra men and 14 extra women would develop cancer at some point in their lives, the researchers said. The higher risk among women is mainly due to the link between alcohol consumption and breast cancer.

This risk was comparable to smoking five cigarettes per week for men and 10 for women.

A "known carcinogen"

"Everybody knows that cigarettes cause cancer," Saitz told Live Science. "Hearing that some amount of alcohol is the equivalent of some amount of cigarettes" in terms of cancer risk, is helpful for the general public, he said.

Saitz noted that there's been little discussion of the cancer risks tied to alcohol, even though alcohol is a known carcinogen. Even dietary guidelines discuss the recommended number of alcoholic drinks per day.

"If I didn't call it alcohol or wine or beer or cocktails, and I just called it a carcinogen, no one would be talking about how many glasses of a carcinogen you could have," Saitz said.

The study authors noted that because the study only considered cancer risk, it didn't take into account other diseases tied to smoking or alcohol use, such as respiratory, cardiovascular or liver diseases.

The authors also pointed out that smokers typically consume far more than five to 10 cigarettes per week — the average smoker in the U.K. consumes around 80 cigarettes per week, and the average smoker in the U.S. consumes around 100 cigarettes per week.

Still, "these findings highlight moderate levels of drinking as an important public health issue," the authors concluded.