The study found that people who increased their drinking had a higher risk of all cancers, including alcohol-related cancers, than the group who didn’t change their drinking habits.
The risk also increased for non-drinkers who changed their habits and became light, moderate, or heavy drinkers.
“This is another great example of how behavior change could significantly reduce cancer deaths,” said Dr. William Dahut, scientific director of the American Cancer Society, told CNN in an email. “The most striking finding is the impact on cancer deaths of changes in alcohol consumption. Individuals should be cautioned that they can drastically reduce their risk of cancer by moderating alcohol consumption.”
The study examined data from more than 4.5 million participants. Study participants were from the Korean National Health Insurance Service, were 40 years of age and older, had completed national health screening in 2009 and 2011, and had available data on their drinking status.
“In this large cohort study using repeated measures of alcohol consumption, we found that individuals who increased their alcohol consumption, regardless of their initial drinking level, had an increased incidence of alcohol-related and all cancers compared to those who maintained their current levels of drinking,” write the study authors from Seoul National University Hospital. “Quitting was not associated with a lower incidence of alcohol-related cancer, but when abstinence was maintained over time, the incidence of alcohol-related and all cancers tended to decrease.”
In those who increased their alcohol consumption because they did not drink, the researchers found a high incidence of stomach, liver, gallbladder and lung cancer, multiple myeloma and leukemia.
They also found that there was an association between a reduced risk of alcohol-related and all cancers and reducing heavy drinking to moderate or light drinking.
First, the two alcohol use assessments were two years apart, with a maximum follow-up of seven years, and the authors had no details about the participants’ alcohol use earlier in life, meaning they could not examine long-term changes.
Information was also lacking on other healthy behaviors that might have occurred alongside reducing alcohol consumption, so the risk changes may not be solely due to alcohol consumption.
There was also no discussion of alcohol-induced hot flashes and an inherited deficiency in an enzyme involved in breaking down alcohol, which is common in East Asian populations. The authors of the editorial said more research is needed in other racial and ethnic groups.
Despite the limitations, the editors’ authors said the research provides “important, new insights into the potential role of changes in alcohol consumption in cancer risk” and suggests future studies follow suit, examining the association in other populations and longer intervals between use the ratings .
The American Cancer Society lists alcohol consumption as “one of the most important avoidable risk factors for cancer, along with tobacco use and obesity”.
The organization says drinking accounts for about 6% of all cancers and 4% of all cancer deaths in the US.
According to the ACS and the US Centers for Disease Control and Prevention, alcohol consumption can increase the risk of six types of cancer: mouth and throat, larynx, esophagus, colon and rectum, liver and breast in women.
ACS also says drinking alcohol likely increases your risk of stomach cancer and some others.
“For each of these types of cancer, the more alcohol you drink, the higher your risk of cancer,” says ACS. “But for some types of cancer, particularly breast cancer, drinking even small amounts of alcohol can increase the risk.”
“I think it’s very important that people realize that heavy drinking can significantly increase the risk of cancer,” Dahut said. “Unfortunately, while this is not a new finding, this information would be very surprising to many. It is imperative that physicians educate patients about this risk and provide all the tools needed to help patients change this behavior.”