Moderate alcohol use is linked to a substantially higher risk of several forms of cancer, including breast, colon, and oral cancers, according to a new study by international researchers. The paper was published in The Lancet Oncology.
"Alcohol consumption causes a substantial burden of cancer globally," said Dr. Isabelle Soerjomataram, one of the authors behind the study. "Yet the impact on cancers is often unknown or overlooked, highlighting the need for implementation of effective policy and interventions to increase public awareness of the link between alcohol use and cancer risk, and decrease overall alcohol consumption to prevent the burden of alcohol-attributable cancers."
For the study, the researchers used estimates on alcohol consumption from the Global Information System on Alcohol and Health taken in 2010, assuming a 10-year latency period between consuming alcohol and developing cancer. To calculate risk outcomes, they used data from systematic literature reviews as a part of the WCRF Continuous Update Project.
They then applied this data to that on cancer incidence from GLOBOCAN 2020 to estimate how many cancer cases could be linked to alcohol. Alcohol consumption was split into three groups: <20mg per day as 'moderate', 20-60g per day as risky, and >60g per day as heavy. They also monitored the effects of alcohol consumption up to 150g per day in 10 g increments.
In the end, the researchers found that 741, 300, or 4.1% of new cancer cases in 2020, were linked to alcohol consumption. Males accounted for 77% of all cancer cases due to alcohol. Cancer of the esophagus, liver and breast, were the most common- each with 189,700, 154,700, and 98,300 attributable cases.
While risky and heavy drinking accounted for most cases of cancer, moderate drinking contributed to 103,100 cases. The researchers also found that rinking up to 10mg per day contributed to 41,300 cases.
"Alcohol causes cancer in numerous ways," explained Dr. Kevin Shield co-author of the study. "The main mechanism of how alcohol causes cancer is through impairing DNA repair. Additional pathways include chronic alcohol consumption resulting in liver cirrhosis, and alcohol leading to a dysregulation of sex hormones, leading to breast cancer. Alcohol also increases the risk of head and neck cancer for smokers as it increases the absorption of carcinogens from tobacco."
The researchers say that the link between light to moderate drinking and cancer is relatively new and so is not currently reflected in public policies. Dr. Juergen Rehm, one of the study's authors, recommends higher taxes on alcohol to better reflect its disease burden, as well as limiting its physical availability and marketing.