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

OXFORD, England — If you enjoy a glass of wine or beer every night, a study may make you think twice about the next time you need to relax. New research warns that alcohol consumption can be blamed for the development of several types of cancer.

Additionally, the University of Oxford study suggests that people who never drink, or who only drink an occasional sip, are 31% less likely to develop certain types of the disease.

Alcohol has been linked to a range of tumours, including those of the breast, bowel, mouth, throat and liver. Now scientists have shown it to be a deadly trigger, especially for those with specific genetic mutations.

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

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

Genes matter

The British team followed more than 150,000 men and women in China for an average of eleven years. Alcohol causes approximately 3 million deaths a year worldwide, including more than 400,000 due to cancer. Consumption is increasing, especially in rapidly developing countries.

But it was 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 such as lung and stomach cancer.

Working with experts in China, Dr. Im and his colleagues used a new approach by studying two variants linked to low alcohol consumption. The genes, called ALDH2 and ADH1B, are common in Chinese and East Asian populations, but rare in Europeans. They feed a cancer-causing compound called acetaldehyde into the blood, causing an unpleasant feeling of “redness”. The mutations were used as a proxy for alcohol consumption. They are inherited at birth independent of other lifestyle factors.

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

Men who carried two copies of ALDH2 drank very little. They had 31% less risk of cancers of the esophagus, colon, rectum and liver. They also had a 14% lower risk of developing 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 only one copy had significantly higher risks of head and neck cancer and esophageal cancer.

Reducing alcohol consumption is an easy way to reduce cancer risk

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

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

The results, published in the International Journal of Cancer, adding to the evidence that abstaining from alcohol is the healthier option.

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

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

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