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Critique 246: Light to moderate alcohol intake and the risk of cancer  —  8 February 2021

The present paper attempts to use alcohol-attributable data, based on combining average alcohol intake from diverse European populations, to judge the effects of moderate alcohol consumption on the risk of cancer for all populations.  It is based on earlier calculations of risk, extensively covered in previous publications by the senior author.  The investigators conclude that the risk of a number of types of cancer are increased even among subjects reporting no more than 20 grams of alcohol per day (up to about 2 typical drinks), an amount they state to be within recommended levels of consumption (but exceed current US Drinking Guidelines for women of no more than 1 drink/day).  The largest contribution to their calculated effects of alcohol was from breast cancer in women (which made up “68.7% of all alcohol attributable cancer for both sexes”).  Breast cancer is a condition for which many factors other than just average alcohol intake are important: factors such as pattern of drinking, type of beverage, folate intake, smoking, obesity, physical activity, etc., all of which tend to confound the association.

Forum members had real concerns about their methodology of using an estimate of “alcohol-attributable cancer” based on reported average intake from 28 separate countries, including the  large countries in western Europe (e.g., Germany, France, UK, Italy, Spain, Sweden), East-European countries (such as Poland and Hungary), and many smaller countries (e.g., Malta, Cyprus, Luxembourg, Latvia).  Given the marked variation in culture and drinking patterns among these countries, it was considered that there are a large number of confounders and modifiers of alcohol effects that vary by country, and make it impossible to simply take the average alcohol intake from such diverse cultures to estimate causality of alcohol and cancer for everyone.  By lumping data from all of these countries, the analyses end up with values that relate to a non-existent hypothetical population; different countries have different risk relationships, so the estimates of effect described in the paper apply to no single country.

Further, the investigators do not report rates of other outcomes, especially total mortality, associated with drinking.  Taking only one outcome condition, without at least noting that moderate drinking has almost uniformly been found to decrease all-cause mortality, limits the usefulness of their results for setting alcohol guidelines.  Heavy alcohol use is recognized by all as a serious impediment to the health of individuals, and to society at large.  However, recommending lowering the intake of alcohol for everyone does not take into consideration that light drinkers might be more likely than heavy drinkers to follow such advice and might decrease their consumption to zero.  Because of moderate drinking’s almost uniformly demonstrated beneficial effect on cardiovascular disease, if many light drinkers stopped drinking completely it would be expected to increase, rather than decrease, total mortality rates and the health of the population.

In their conclusions, the authors only mention the results of their actual analyses briefly, then start the usual chant of the need for extensive public health measures (warning labels, public information campaigns, increasing alcohol taxes, etc.) which tend to emphasize the dangers of any alcohol consumption.  However, the analyses in this paper do not provide the data that are needed if one is to set appropriate drinking guidelines, which should be age-specific, sex-specific, and population-specific.  Such factors would include not only the alcohol-disease relation but the particular characteristics of the population, the objective of guidelines (to influence and change behavior among target populations), the behavior that is thought to be in need of change, the culture and mindset of the target population, and the kind of message that is likely to be effective.  Forum members realize that there are tensions between advice intended only to reduce the prevalence of misuse versus advice that takes into account the well demonstrated beneficial health effects of light-to-moderate consumption.  When setting guidelines, it is important to take into account the prevailing drinking culture of a country or population, because only in that way is it possible to produce a public health message that is likely to be respected and regarded.

Reference: Rovira P, Rehm J.  Estimation of cancers caused by light to moderate alcohol consumption in the European Union.  European Journal of Public Health 2021; pre-publication. doi:10.1093/eurpub/ckaa236.

 

For the full critique of this paper by the International Scientific Forum on Alcohol Research, please click here
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