Around 20 New Zealand women die a year from breast cancer linked to consuming fewer than two alcoholic drinks a day on average, a new University of Otago study has found.
Drinking alcohol is a known cause of various types of cancer.
"About 60% of all alcohol-attributable cancer deaths in New Zealand women are from breast cancer," said Professor Jennie Connor, the lead author of the new study, published in the international journal Drug and Alcohol Review.
"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."
Around 600 women die from breast cancer each year in New Zealand.
The cancers 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.
The study uses evidence that alcohol causes some types of cancer after combining dozens of large studies conducted internationally over several decades.
The researchers found that drinking alcohol was responsible for 236 cancer deaths in people aged under 80 in New Zealand in 2012.
The research, in collaboration with the Global Burden of Disease Alcohol Group, builds on previous work that identified 30% of all alcohol-attributable deaths in New Zealand to be due to cancer, more than all other chronic diseases combined.
Professor Connor said, "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."
"These premature deaths from cancer resulted in an average 10.4 years of life lost per person affected, with more loss of life among Maori than non-Maori, and for breast cancer compared with other cancers."
"While these alcohol-attributable cancer deaths are only 4.2% 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."
Alcohol and cancer in New Zealand, 2012
236 - estimated number of cancer deaths linked to to alcohol consumption in people under 80.
10.4 - average years of life lost per person who died.
65 - estimated number of breast cancer deaths linked to alcohol consumption in women under 80.
Source: University of Otago
