PARIS -- Alcohol consumption was linked to 4% of all new global cancer cases last year, according to a study published Wednesday, as researchers warned of an urgent need to alert people of the risks.
Men accounted for more than three quarters of the estimated cases, which were mainly linked to risky or heavy drinking, although one in seven of these alcohol-related cancers were linked to moderate consumption of around two drinks a day.
The study, published in the journal The Lancet Oncology, estimated that there were more than 6.3 million cases in 2020 of mouth, pharynx, voice box larynx, oesophageal, colon, rectum, liver, and breast cancer -- all of which have established links to alcohol.
Researchers also used a selection of data on alcohol sales, production, tax, and consumption to estimate how much people drank per day in countries around the world in 2010 -- giving a decade for the effect to materialize in possible cancer cases.
They estimated that 4% (741,300) of all new cases of cancer around the world in 2020 were associated with alcohol consumption, with men accounting for 77% (568,700 cases) of these and women 23%.
The study found that the number of new cancer cases linked to alcohol consumption varied widely across the world, with the highest rates seen in East Asia and Central and Eastern Europe and the lowest in North Africa and Western Asia.
The highest proportion of alcohol-related cases were estimated in Mongolia, China, Moldova, and Romania, while the lowest were in Kuwait, Libya, and Saudi Arabia.
The parts of the world with the highest proportion of women estimated to have new alcohol-related cancer included in Belarus, Romania and Russia, Australia and New Zealand and Western Europe.
Cancers of the esophagus (189,700 cases), liver (154,700), and breast (98,300) were the most common.
"We urgently need to raise awareness about the link between alcohol consumption and cancer risk among policy makers and the general public," said study author Harriet Rumgay of the International Agency for Research on Cancer in France, in a press release.
The authors point to previous research that found alcohol consumption causes DNA damage and can affect hormone production, which can contribute to cancer development.
They said limitations on the research included COVID-19 disruptions to health care, which may have led to fewer people being diagnosed with cancer last year than would be shown in their estimates.
Rumgay said measures like reducing the availability of alcohol, health warning labels, taxation and marketing bans "could reduce rates of alcohol-driven cancer", calling for strategies tailored to specific regions.
"Such policies have a strong evidence base for reducing alcohol harm," said Sadie Boniface, head of research at the Institute of Alcohol Studies at King's College London, in a commentary on the research.
Boniface, who was not involved in the study, said the results were broadly in line with other research and that scientists already know the links to seven types of cancers.
But she said there was "low public awareness of this risk, particularly for breast cancer".