Alcohol consumption contributes to cancer, even in moderate drinkers

Drinking alcohol increases the risk of several types of cancer, and was responsible for 236 cancer deaths under 80 years of age in New Zealand in 2012, according to a new study at the University of Otago.

The research, in collaboration with the Global Burden of Disease Alcohol Group, and just published in the international journal Drug and Alcohol Review, builds on previous work that identified 30 per cent of all alcohol-attributable deaths in New Zealand to be due to cancer, more than all other chronic diseases combined.

The study uses evidence that alcohol causes some types of cancer after combining dozens of large studies conducted internationally over several decades. The cancers that are known to be causally related to alcohol include two of the most common causes of cancer death in New Zealand, breast and bowel cancer, but also cancer of the mouth, pharynx, oesophagus, larynx and liver. This New Zealand study estimated mortality for 2007 and 2012.

Lead author, Professor Jennie Connor of the Department of Preventive and Social Medicine at Otago Medical School, said the findings about breast cancer were particularly sobering.

"About 60 per cent of all alcohol-attributable cancer deaths in New Zealand women are from breast cancer. We estimated 71 breast cancer deaths in 2007 and 65 in 2012 were due to drinking, and about a third of these were associated with drinking less than two drinks a day on average. Although risk of cancer is much higher in heavy drinkers there are fewer of them, and many alcohol-related breast cancers occur in women who are drinking at levels that are currently considered acceptable," Professor Connor says.

"There was little difference between men and women in the number of cancer deaths due to alcohol, even though men drink much more heavily than women, because breast cancer deaths balanced higher numbers of deaths in men from other cancer types."

She adds: "These premature deaths from cancer resulted in an average 10.4 years of life lost per person affected, with more loss of life among Māori than non-Māori, and for breast cancer compared with other cancers."

"While these alcohol-attributable cancer deaths are only 4.2 per cent of all cancer deaths under 80, what makes them so significant is that we know how to avoid them," explains Professor Connor.

"Individual decisions to reduce alcohol consumption will reduce risk in those people, but reduction in alcohol consumption across the population will bring down the incidence of these cancers much more substantially, and provide many other health benefits as well.

"Our findings strongly support the use of population-level strategies to reduce consumption because, apart from the heaviest drinkers, people likely to develop cancer from their exposure to alcohol cannot be identified, and there is no level of drinking under which an increased risk of cancer can be avoided.

"We hope that better understanding of the relationship of alcohol with cancer will help drinkers accept that the current unrestrained patterns of drinking need to change."