New research led by the Daffodil Centre, a joint venture between Cancer Council NSW and the University of Sydney, has identified that alcohol may cause more deaths than previously thought, as evidence reviews over the past 30 years may have underestimated the number of deaths caused by alcohol due to an issue called the ‘sick-quitter effect’.
The study, published today in the journal Addiction, adds urgency to the need for governments to do more to highlight the risks associated with alcohol, particularly various types of cancer including liver and breast cancer, and to support policies that put public health before alcohol industry interests.
Study lead, Dr Peter Sarich, said that more than 70% of global systematic reviews on alcohol health harms since 1993 used non-drinkers as the comparator to people who consume any alcohol, which can cause biased results.
“Many people identified as non-drinkers in cohort studies are in fact former heavy drinkers who have incurred health harms which actually caused them to quit drinking in the first place,” Dr Sarich said.
“This can lead to the ‘sick quitter effect’ – people with compromised health due to previous drinking behaviours who appear in health data as non-drinkers, when in fact they are ex-drinkers with health problems. When a study compares to this group of people, it can falsely make the harms of drinking appear smaller or non-existent, or even make it seem like drinking small quantities of alcohol protects against harms”.
Dr Sarich said that of the 30% of reviews that were not affected by the ‘sick-quitter’ issue, only one was considered a high-quality review, and found that the risk of death increases with increasing alcohol intake, with no evidence of any protective effects for low-level drinking. All of the remaining reviews may have understated the health harms of alcohol.
Dr Sarich hopes that these findings encourage Australians to follow the National Health and Medical Research Council (NHMRC) guidelines on alcohol use.
“While there is no healthy amount of alcohol, the NHMRC guidelines state that Australian adults should drink no more than 10 standard drinks per week, with no more than 4 drinks on any one day. The less you drink, the lower your risk of harm from alcohol.
“However, the 2022-23 National Drug Strategy Household Survey showed that 32% of us are exceeding this guideline, and even more concerning are the recent statistics from the ABS finding that alcohol-induced deaths in Australia have been increasing over the past 10 years. Of all deaths caused by alcohol in Australia, a large portion are from cancer. The more people drink, the higher their risk of dying from one of the seven types of cancer that are caused by alcohol, according to previous Cancer Council research.”
Ms Clare Hughes, Chair of Cancer Council’s national Nutrition, Alcohol and Physical Activity Committee, said alcohol causes more cancer deaths each year than UV radiation, yet awareness of the risks in Australia was low.
“The International Agency for Research on Cancer classifies alcohol as a Group 1 carcinogen meaning there is strong evidence that alcohol use increases the risk of several cancers such as cancer of the breast, bowel, mouth and throat, oesophagus, and liver.” Ms Hughes said.
“Yet a 2023 nation-wide survey found that only 46% of Australians were aware of the link between drinking and cancer, including only 14% who were aware that alcohol causes breast cancer.
“This new review strengthens the evidence surrounding the harms of alcohol use and highlights the need for urgent action. We’d like to see governments invest in a campaign to raise awareness of the long-term health risks associated with alcohol use, and implement policies to address the pricing, availability, and advertising of alcohol, that have been shown to help reduce alcohol use in the community.
