The nectar of the gods has a problem.
While evidence suggests a moderate amount of alcohol, typically red wine, may conjure some health benefits, a growing body of research points to the complex, negative ways alcohol interacts with the body. Alcohol is responsible for 1 in 20 deaths globally — in a new study, scientists claim this number might be even higher.
In this worldwide analysis, researchers found 4 percent of all newly diagnosed cancers in 2020 may be associated with alcohol use. Men accounted for more than three-quarters of those cases.
These numbers are especially significant considering the fact that many doctor’s offices paused cancer screenings during Covid-19. It’s possible these case counts are higher. It’s also something to keep in mind for the future: Global alcohol use increased during the pandemic.
Study co-author Harriet Rumgay is a researcher at the World Health Organization’s International Agency for Research on Cancer. “Alcohol causes a substantial burden of cancer globally,” she tells Inverse. “This is evident even at lower levels of drinking.”
Can you get cancer from alcohol?
Different cancers associated with alcohol are likely ignited by different forces, Rumgay says. She offers three examples:
- DNA damage: Alcohol (as ethanol, which is the chemical compound of alcohol) is converted in our bodies into another chemical called acetaldehyde. Acetaldehyde can cause DNA damage and stop DNA repair in cells of specific tissues or organs, which may lead to cancer.
- Liver cirrhosis: Alcohol damages the cells of the liver and can cause a disease called liver cirrhosis. Cirrhosis makes you more likely to develop liver cancer.
- Hormones: Alcohol can increase the levels of some hormones, such as estrogen. High levels of estrogen increase the risk of breast cancer.
What’s new — Rumgay and colleagues first pulled country-specific estimates of cancer incidence and mortality data stored in GLOBOCAN2020, a database produced by the International Agency for Research on Cancer.
They then obtained 2010 data from the Global Information System on Alcohol and Health.
“We chose a period of 10 years between alcohol drinking and cancer diagnosis based on the studies we used which looked at how much cancer risk increases from drinking alcohol,” Rumgay explains. “The average length of these studies was around 10 years.”
The researchers then took the two data sets and used population attributable fractions (PAFs) to estimate the effect risk factors had on disease burden.
“This is a really useful indicator to provide support for decisions about managing risks associated with those specific risk factors or diseases,” Rumgay says. “In this case, we used PAFs to estimate how many cases of cancer could have been avoided if no one in the population consumed alcohol.”
They made these estimated PAFs by combining data on alcohol consumption, the increased risk of developing cancer from drinking alcohol, and estimates of the number of cases of cancer in the population.
What was discovered — Four percent of all newly diagnosed cancers in 2020 may be associated with drinking alcohol, the study suggests. That’s more than 740,000 new cancer cases.
Unsurprisingly, heavy and risky drinking was estimated to contribute to the highest number of cancer cases. But moderate drinkers aren’t in the clear: The equivalent of two daily drinks was estimated to result in more than 103,000 new cancer cases in 2020, nearly 1 in 7 of all alcohol-associated cases.
While the proportion of alcohol-associated cancer cases varied by region, some of the results surprised Rumgay.
“We were very interested to see that Eastern Asia had a higher proportion of alcohol-attributable cancers than Central and Eastern Europe in our estimates,” she says.
“Central and Eastern Europe had the highest population alcohol use worldwide for decades, but this has shifted as alcohol consumption has decreased over time in Europe and has increased in Eastern Asia.”
Why men are especially at risk — Perhaps the most striking result to come from the study was the gender disparity in alcohol-associated cancers.
The study estimates that men accounted for 77 percent of alcohol-associated cancer cases. Women accounted for 23 percent of cases. That’s 568,700 new cancer cases for men, and 172,00 for women.
Rumgay says this difference can be distilled down to differences in alcohol intake.
“Most of the difference between the results for men and women is due to different levels of alcohol use,” she says. “Global estimates for 2017 showed that men drank more than three times the amount of alcohol on average per year than women.”
What it means for the future– Rumgay would like to see this study contribute to a better global understanding of the link between alcohol use and cancer.
“Alcohol’s impact on cancer is often unknown,” she says. “We need to increase public awareness of the link between alcohol consumption and cancer risk, and policies to decrease overall alcohol consumption to prevent the burden of alcohol-attributable cancers and other diseases.”
Background: Alcohol use is causally linked to multiple cancers. We present global, regional, and national estimates of alcohol-attributable cancer burden in 2020 to inform alcohol policy and cancer control across different settings globally.
Methods: In this population-based study, population attributable fractions (PAFs) calculated using a theoretical minimum-risk exposure of lifetime abstention and 2010 alcohol consumption estimates from the Global Information System on Alcohol and Health (assuming a 10-year latency period between alcohol consumption and cancer diagnosis), combined with corresponding relative risk estimates from systematic literature reviews as part of the WCRF Continuous Update Project, were applied to cancer incidence data from GLOBOCAN 2020 to estimate new cancer cases attributable to alcohol. We also calculated the contribution of moderate (<20 g per day), risky (20–60 g per day), and heavy (>60 g per day) drinking to the total alcohol-attributable cancer burden, as well as the contribution by 10 g per day increment (up to a maximum of 150 g). 95% uncertainty intervals (UIs) were estimated using a Monte Carlo-like approach.
Findings: Globally, an estimated 741 300 (95% UI 558 500–951 200), or 4·1% (3·1–5·3), of all new cases of cancer in 2020 were attributable to alcohol consumption. Males accounted for 568 700 (76·7%; 95% UI 422 500–731 100) of total alcohol-attributable cancer cases, and cancers of the oesophagus (189 700 cases [110 900–274 600]), liver (154 700 cases [43 700–281 500]), and breast (98 300 cases [68 200–130 500]) contributed the most cases. PAFs were lowest in northern Africa (0·3% [95% UI 0·1–3·3]) and western Asia (0·7% [0·5–1·2]), and highest in eastern Asia (5·7% [3·6–7·9]) and central and eastern Europe (5·6% [4·6–6·6]). The largest burden of alcohol-attributable cancers was represented by heavy drinking (346 400 [46·7%; 95% UI 227 900–489 400] cases) and risky drinking (291 800 [39·4%; 227 700–333 100] cases), whereas moderate drinking contributed 103 100 (13·9%; 82 600–207 200) cases, and drinking up to 10 g per day contributed 41 300 (35 400–145 800) cases.
Interpretation: Our findings highlight the need for effective policy and interventions to increase awareness of cancer risks associated with alcohol use and decrease overall alcohol consumption to prevent the burden of alcohol- attributable cancers.