Alcohol ‘directly causes several types of cancer,’ doctors warn

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OXFORD, England — If you enjoy a nightly glass of wine or beer, one study may have you thinking twice next time you need to take the edge off. New research warns that alcohol consumption can be blamed for the development of multiple types of cancer.

Moreover, the study out of Oxford University suggests that people who never drink, or just have an occasional sip, are 31 percent less likely to develop certain types of the disease.

Alcohol has been linked to a range of tumors including those of the breast, bowel, mouth, throat and liver. Now, scientists have shown it is a lethal trigger, especially for those with specific gene mutations.

“These findings indicate alcohol directly causes several types of cancer,” says lead researcher Dr. Becky Im, of Oxford Population Health, in a statement. “These risks may be increased further in people with inherited low alcohol tolerability who cannot properly metabolize alcohol.”

Authors say the risks were greatest in participants who drank regularly despite being more prone to the effects.

Genes matter

The British team tracked more than 150,000 men and women in China for an average of eleven years. Alcohol claims about 3 million lives a year across the globe — over 400,000 from cancer. Consumption is rising, particularly in fast developing countries.

But it has been difficult to rule out confounding factors, such as smoking and diet, that could generate biased results. It was also unclear whether alcohol causes other forms like lung and stomach cancer.

Working with experts in China, Dr. Im and colleagues used a novel approach by investigating two variants linked to low alcohol intake. The genes, known as ALDH2 and ADH1B, are common in Chinese and East Asian populations, but rare in Europeans. They fuel a carcinogenic compound called acetaldehyde in the blood, leading to an unpleasant “flushing” feeling. The mutations were used as a proxy for alcohol intake. They are inherited at birth independent of other lifestyle factors.

Men with one or two copies of ADH1B were 13 to 25 percent less likely to get any cancer. The phenomenon applied particularly to alcohol-related tumors, specifically those of the head, neck and esophagus.

Men who carried two copies of ALDH2 drank very little. They had 31 percent lower risk of cancers of the esophagus, colon, rectum and liver. They also had a 14 percent lower risk of developing any cancer.

Since women rarely drink alcohol in China, the main analysis focused on men, a third of whom indulged most weeks. Those who drank regularly despite carrying one copy had significantly higher risks of head and neck cancer and esophageal cancer.

Lowering alcohol consumption is an easy way to lower risk of cancer

For those who completely abstain or occasional drinkers, there was no overall association between carrying one copy of ALDH2 and increased cancer risk. The results remained the same when smoking, diet, physical activity, body mass and family history of cancer were taken into account.

In the women, only 2 percent of whom drank regularly, the mutations were not associated with any increased risk of cancer. This indicated the reduced risks for male carriers resulted from their lower alcohol consumption.

The results, published in the International Journal of Cancer, add to evidence abstaining from alcohol is the healthiest option.

“Our study reinforces the need to lower population levels of alcohol consumption for cancer prevention,” says senior researcher Dr Iona Millwood, also from Oxford.

South West News Service writer Mark Waghorn contributed to this report.