New Zealand researchers said on Friday that there is strong evidence that alcohol is a direct cause of cancer.
A review of epidemiological evidence supported a causal association between alcohol consumption and cancers at seven sites in the body: oropharynx, larynx, oesophagus, liver, colon, rectum and female breast, said Prof. Jennie Connor, a University of Otago researcher.
While there was a long-recognized association between alcohol and cancer, a "causal association" meant there was evidence that alcohol consumption directly caused cancer, Connor said in a statement.
The causal link was supported by evidence for a dose-response relationship, at least partial reversal of risk when alcohol consumption was reduced, statistical adjustment for other factors that might explain the association, and specific association with some cancers and not others.
The review cited evidence that alcohol caused approximately half a million deaths from cancer in 2012, or 5.8 percent of cancer deaths worldwide.
The highest risks were associated with the heaviest drinking, but a considerable burden was experienced by drinkers with low to moderate consumption.
The review also found the evidence that moderate drinking provided protection against cardiovascular disease was not strong.
