Alcohol causes 7 kinds of cancer, study concludes

CTV News Channel: Alcohol linked to cancer Alcohol researcher Jennie Connor says the link is a causal one and that no alcohol is considered safe and risk does go up as you drink.

Alcohol is a direct cause of seven forms of cancer. Tough words to swallow, but those are the conclusions of researchers from New Zealand, who say they found that no matter how much you drink, alcohol will increase your risk of cancer.

“There is strong evidence that alcohol causes cancer at seven sites in the body and probably others,” the authors write in the latest issue of the journal Addiction.

Those seven cancer sites are:

The researchers from the University of Otago reviewed previous studies and meta-analyses, analyzing all the major studies done over the last decade on alcohol and cancer. They include studies from such prestigious names as the American Institute for Cancer Research and the International Agency for Research on Cancer.

Several of these studies drew links between alcohol and cancer. But lead researcher Jennie Connor, the chair in preventive and social medicine at the university, says her team wanted to know if there was evidence of a causal relationship -- meaning that alcohol was the direct cause of some of these cancers.

“And the first conclusion of the paper is that there is very strong evidence that the link we see between drinking and cancer in all these studies is a causal one,” Connor told CTV News Channel from Dunedin, New Zealand.

In fact, the team estimates that of all cancer deaths worldwide, 5.8 per cent of them can be attributed to alcohol.

The link between alcohol and cancer was strongest with cancer of the larynx and orolarynx than with the other cancers

Perhaps not surprisingly, the team found a "dose-response relationship" between alcohol and cancer, meaning that the more that a person drinks, the higher their risk to develop cancer.

So what constitutes a “safe” level of drinking?

“There doesn’t seem to be any threshold below which drinking is actually safe with respect to cancer,” Connor said.

“So the straightforward obvious answer to your question is that no alcohol is safe, and any alcohol increases your risk of some types of cancer.”

One bit of good news is that the cancer risk will drop for those who quit drinking, falling back to risk levels similar to “never drinkers” after 20 years.

As for what it is about alcohol that causes cancer, the researchers aren’t sure, as their paper was not designed to answer such questions.

“Confirmation of specific biological mechanisms by which alcohol increases the incidence of each type of cancer is not required to infer that alcohol is a cause,” they wrote.

This is not the first paper to conclude that alcohol is carcinogenic, and yet there persists a perception that a small amount of alcohol is not only safe but beneficial.

Many point to studies that found that drinking wine is good for the heart increases longevity. Connor says that there are a still a lot of myths about alcohol out there.

“(These myths) arise from research that has been updated now, or discredited, or there’s more doubt about it than they used to be,” she said.

“This paper also examines the connection between alcohol and being good for your heart – coronary disease – and it finds that evidence base is actually quite weak. So information evolves over time.”