(Creative Commons photo via Flickr user preciouskhyatt)
[See bottom of article for update]
Should you quit drinking to reduce your risk of cancer? That’s the question many Americans might be asking themselves after the flurry of media reports claiming that even light alcohol consumption increases your risk of cancer. The reports focus on a recently released study, funded by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) titled, “Alcohol-Attributable Cancer Deaths and Years of Potential Life Lost in the United States,” and published in the American Journal of Public Health on February 14, has numerous methodological problems that cast serious doubt on its conclusions—but you’d never know that from the headlines it has generated. Moreover, people who choose to abstain from alcohol entirely because of this study could significantly increase their risk of dying from much more common diseases. Rather than jumping to the conclusion that alcohol is unsafe at any level, consumers should weigh the costs and benefits and consider their own personal needs and risks.
The study sought to determine how many cancer deaths are attributable to alcohol consumption. Certainly, heavy use of alcohol is associated with certain cancers, such as esophageal and liver cancer, but these types of cancers take decades of heavy alcohol. The mechanism by which alcohol consumption may lead to cancer isn’t yet understood and it is important that scientists examine how patterns of consumption, genetics, or nutrition affect the risk of developing cancer. While the authors of this study note that biological mechanism of how alcohol might spur or cause cancer isn’t understood, fail to put their results into the wider context of current research. They looked at mortality data from just one year, 2009, and “corrected” it to account for the underreporting of alcohol consumption which they assume occurs in the surveys they examined. While it’s widely understood that data from self-reporting in surveys is error-prone, as Dr. Curtis Ellison of Boston University noted in his critique of the study for the International Scientific Forum on Alcohol Research, the method the authors employed to correct the data is not one generally accepted by statisticians or other researchers. This, as Ellison notes “means that even many ‘light’ drinkers are listed as reporting greater amounts of alcohol.”
The authors of the study also neglected to account for how people drink as well as how much. Previous studies examining the link between alcohol and cancer have determined a slightly increased risk from binge drinking behavior. But this study’s most damning element (apart from the fact that it is a textbook example of white hat bias) is its authors’ failure to put their conclusions into context. Perhaps, they didn’t want to talk about previous studies, including one from other NIAAA scientists that questioned the link between alcohol and breast cancer.
But by far the most egregious offence is that the authors willfully ignore the proven health benefits of alcohol on health while promoting their message that no level of alcohol consumption is safe. Yet, countless studies have shown time and again that drinkers have a far smaller risk of mortality than their non-drinking counterparts. According to the Harvard School of Public Health’s overview on alcohol’s risks and benefits, “More than 100 prospective studies show an inverse association between moderate drinking and risk of heart attack, ischemic (clot-caused) stroke, peripheral vascular disease, sudden cardiac death, and death from all cardiovascular causes,” ultimately resulting in a “25 percent to 40 percent reduction in risk.” That is especially significant, given that heart-related diseases kill people in this country than all cancers combined. If light and moderate alcohol drinkers abstained to avoid becoming one of the 19,500 people the study claims had alcohol-related cancers, we would almost certainly see an increase in the number of heart disease-related deaths, which according to the CDC account for about 600,000 deaths in the U.S. each year.
The authors make no attempt to moderate their message; they want to convince people that drinking at any level is unsafe. That is despite the shaky ground on which their conclusions rest and the countless other studies which have questioned the link between alcohol and cancer and demonstrated the health benefits of alcohol consumption.
So does this kind of scare mongering from the NIAAA do any good, other than to help justify the $460 million a year it receives from taxpayers? Certainly, a greater understanding of cancer’s risk factors is important, but research with an agenda does little to increase our body of scientific knowledge. In the end, it is little more than headline fodder for attention-seeking news media that could result in a population that is sicker rather than healthier.
Editor's note: This article has been edited to remove a criticism of the NIAAA study that the authors addressed in the study. The introduction and conclusion have also been changed to reflect the retraction of that criticism.