August 24, 2022
3 min read
The researchers report no relevant financial disclosures. Abnet and Freedman report no relevant financial disclosures.
Individuals who increased alcohol consumption had higher risks for both alcohol-associated and all cancer types, according to results of a Korean population-based cohort study published in JAMA Network Open.
However, those who reduced their drinking or maintained abstinence from alcohol had lower cancer risk, researchers wrote.
Globally, cancer is the second leading cause of death and accounted for an estimated 9.6 million deaths in 2018. Third after tobacco use and excess body weight, alcohol consumption is a key modifiable cancer risk factor and established cause of at least seven cancer types, according to study background.
“Although numerous studies have shown an association between alcohol consumption and cancer, there is paucity of research into how the incidence of cancer increases or decreases with changes in drinking habits,” Jung Eun Yoo, MD, PhD, researcher in the department of family medicine at Healthcare System Gangnam Center of Seoul National University Hospital in Seoul, Republic of Korea, and colleagues wrote. “We found only one cohort study that reported an association between reduction in alcohol consumption and risk [for] cancer.”
To address the research gap, Yoo and colleagues examined the association between reducing, stopping or increasing alcohol consumption and the development of alcohol-associated and all cancer types among 4,513,746 adult beneficiaries (mean age, 53.6 years; 51.5% men) in the Korean National Health Insurance Service database. All study participants underwent national health screenings between 2009 and 2011 and had available data on their drinking status.
Researchers asked participants to self-report their alcohol consumption level as none, mild, moderate or heavy. They then categorized participants into groups based on changes in alcohol consumption levels between 2009 and 2011, including nondrinker, sustainer, increaser, quitter and reducer.
Newly diagnosed alcohol-related cancers, including head and neck, esophageal, colorectal, liver, laryngeal and female breast cancers, served as the primary outcome. All newly diagnosed cancers, except for thyroid cancer, served as the secondary outcome.
Researchers followed participants from 1 year after the 2011 health screening date to the date of incident cancer, death or end of study on Dec. 31, 2018 — whichever occurred first.
Median follow-up was 6.4 years.
Yoo and colleagues reported a rate of cancer incidence for the overall study population of 7.7 per 1,000 person-years.
Results showed that between 2009 and 2011, 26.6% of participants with mild drinking levels stopped drinking vs. 9.6% with moderate and 8.6% with heavy drinking levels.
Compared with participants who sustained their drinking levels, those who increased their drinking levels had a higher risk for both alcohol-associated cancers and all cancers. Researchers additionally found that compared with those who did not drink, those who changed their drinking levels from none to mild (adjusted HR [aHR] = 1.03; 95% CI, 1-1.06), moderate (aHR = 1.1; 95% CI, 1.02-1.18) or heavy (aHR = 1.34; 95% CI, 1.23-1.45) had a higher risk for alcohol-related cancers and all cancers. Conversely, mild drinkers who quit drinking had a lower risk for alcohol-related cancers (aHR = 0.96; 95% CI, 0.92-0.99) compared with those who sustained their drinking levels.
Researchers also observed higher incidence of all cancers among those with moderate (aHR = 1.07; 95% CI, 1.03-1.12) or heavy drinking levels (aHR = 1.07; 95% CI, 1.02-1.12) who stopped drinking compared with those who sustained their drinking levels. However, the increased risk disappeared when participants remained alcohol-free over time.
Moreover, heavy drinkers who reduced their drinking to moderate levels also reduced their risks for alcohol-associated cancers (aHR = 0.91; 95% CI, 0.86-0.97) and all cancers (aHR = 0.96; 95% CI, 0.92-0.99) compared with those who sustained heavy drinking levels. Researchers observed similar risk reductions among those who reduced heavy drinking levels to mild levels (alcohol-associated cancer, aHR = 0.92; 95% CI, 0.86-0.98; all cancers, aHR = 0.92; 95% CI, 0.89-0.96).
Yoo and colleagues reported several study limitations, including the probability that participants may have underreported their alcohol consumption, the unavailability of information about long-term habits, and the lack of pertinent information, such as reasons for reducing or stopping drinking and duration of drinking.
“Findings of this study suggest that drinking cessation and reduction should be reinforced for the prevention of cancer,” the researchers wrote.
Yoo and colleagues’ findings provide important new data about the potential role of changes in alcohol consumption in cancer risk, according to an accompanying editorial by Neal D. Freedman, PhD, MPH, and Christian C. Abnet, PhD, MPH, both researchers in the metabolic epidemiology branch in the division of cancer epidemiology and genetics at NCI.
“Future studies should follow these authors’ lead and examine the association between alcohol intake and cancer risk in other populations and using longer intervals between assessments,” they wrote. “Such studies are needed to move the field forward and inform public health guidance on cancer prevention.”