Alcohol is a major preventable risk factor for cancer. New data suggest that reducing alcohol intake reduces the risk of developing an alcohol-related cancer.
The findings, from a large population-based study conducted in Korea, underscore the importance of encouraging individuals to quit drinking or to reduce alcohol consumption to help reduce cancer risk, the authors noted.
The study was published online in JAMA Network Open.
It provides evidence “suggesting that cancer risk can be meaningfully altered by changing the amount of alcoholic beverages consumed,” wrote the authors of an accompanying editorial, Neal D. Freedman, PhD, and Christian C. Abnet, PhD, of the division of cancer epidemiology and genetics at the National Cancer Institute, Rockville, Md.
they wrote, adding that a “well examined dose-response association has been reported, with highest risks observed among people who drink 3 alcoholic beverages per day and higher.”
The new study shows that a “reduction in use was associated with lower risk, particularly among participants who started drinking at a heavy level,” they noted.
Previous studies have estimated that alcohol use accounts for nearly 4% of newly diagnosed cancers worldwide and nearly 5% of U.S. cancer cases overall.
But the figures are much higher for some specific cancers. That same U.S. study found that alcohol accounts for at least 45% of oral cavity/pharyngeal cancers and at least 25% of laryngeal cancers, as well as 12.1% of female breast cancers, 11.1% of colorectal cancers, 10.5% of liver cancers, and 7.7% of esophageal cancers, as previously reported by this news organization.
New findings on reducing intake
This latest study involved an analysis of data on 4.5 million individuals who were adult beneficiaries of the Korean National Health Insurance Service. The median age of the participants was 53.6 years, and they underwent a national health screening in 2009 and 2011.
During median follow-up of 6.4 years, the cancer incidence rate was 7.7 per 1,000 person-years.
Information on alcohol consumption was collected from self-administered questionnaires completed during the health screenings. Participants were categorized on the basis of alcohol consumption: none (0 g/d), mild ( less than 15 g/d), moderate (15-29.9 g/d), and heavy (30 or more g/d).
Compared with those who sustained their alcohol consumption level during the study period, those who increased their level were at higher risk of alcohol-related cancers and all cancers, the investigators found.
The increase in alcohol-related cancer incidence was dose dependent: Those who changed from nondrinking to mild, moderate, or heavy drinking were at increasingly higher risk for alcohol-related cancer, compared with those who remained nondrinkers (adjusted hazard ratios [aHRs], 1.03, 1.10, and 1.34, respectively).
Participants who were mild drinkers at baseline and who quit drinking were at lower risk of alcohol-related cancer, compared with those whose drinking level was sustained (aHR, 0.96). Those with moderate or heavy drinking levels who quit drinking were at higher overall cancer risk than were those who sustained their drinking levels. However, this difference was negated when quitting was sustained, the authors noted.
For heavy drinkers who reduced their drinking levels, cancer incidence was reduced, compared with those who sustained heavy drinking levels. This was true for those who changed from heavy to moderate drinking (aHR, 0.91 for alcohol-related cancers; 0.96 for alcohol-related cancers) and those who changed from heavy to mild drinking (aHR, 0.92 for alcohol-related cancers and all cancers).
“Alcohol cessation and reduction should be reinforced for the prevention of cancer,” concluded the authors.
Implications and future directions
The editorialists noted that the study is limited by several factors, such as a short interval between assessments and relatively short follow-up. There is also no information on participants’ alcohol consumption earlier in life or about other healthy lifestyle changes during the study period. In addition, there is no mention of a genetic variant affecting aldehyde dehydrogenase that leads to alcohol-induced flushing, which is common among East Asians.
Despite of these limitations, the study provides “important new findings about the potential role of changes in alcohol consumption in cancer risk,” Dr. Freedman and Dr. Abnet noted. Future studies should examine the association between alcohol intake and cancer risk in other populations and use longer intervals between assessments, they suggested.
“Such studies are needed to move the field forward and inform public health guidance on cancer prevention,” the editorialists concluded.
The authors of the study and the editorialists have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.