Alcohol causes seven types of cancer and probably others, a review has concluded.
A study of existing research has found strong evidence of a direct, harmful effect of drinking, but scientists are unsure why.
Writing in the journal, Addiction, Jennie Connor, from the University of Otago, in New Zealand, said alcohol is estimated to have caused about half a million deaths from cancer in 2012, or 5.8% of the total.
Even people who drink at low levels are at risk. The review linked alcohol to cancer of the mouth and throat, larynx, oesophagus, liver, colon, bowel and breast.
Connor said: “There is strong evidence that alcohol causes cancer at seven sites, and probably others. 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.”
She said there is no safe level of drinking with respect to cancer, though the risks are reduced for some cancers when people stop drinking.
The supposed health benefits of drinking — such as red wine being good for the heart — were “seen, increasingly, as disingenuous or irrelevant, in comparison to the increase in risk of a range of cancers,” she said.
In January, the UK’s chief medical officers said no level of regular drinking was without risks to health.
Publishing a raft of recommendations, they said men should consume no more than 14 units of alcohol per week, down from the previous 21 units, bringing them into line with the recommendation for women.
Compared with non-drinkers, women who regularly drink two units a day have a 16% increased risk of developing breast cancer and of dying from it. Those who regularly consume five units a day have a 40% increased risk.
For every 1,000 women who do not drink, 109 will develop breast cancer. This rises to 126 women of those who drink 14 units or less per week, and 153 women of those who drink 14 to 35 units a week.
Scientists are still researching how alcohol can lead to cancer.
One theory is that alcohol damages DNA.
Susannah Brown, the science programme manager for the World Cancer Research Fund (WCRF), said of the new findings: “Many people believe that alcohol consumption is only linked to liver cancer, but this review confirms the findings of our Continuous Update Project that alcohol is strongly linked to an increased risk of a number of different cancers, including two of the most common — bowel and breast cancer”.
© Irish Examiner Ltd. All rights reserved