In an attempt to assess the relation between light alcohol consumption (<12.5g per day) and the risk of a number of types of cancer, the authors carried out a review of meta-analyses published within the past 15 years. Using as keywords “light alcohol drinking,” “light alcohol consumption” and “cancer”, they found 29 meta-analyses on the subject. They report their results as indicating that “Light alcohol drinking was not associated with an increased risk of cancer occurrence, with the exception of breast and prostate cancer and melanoma. Furthermore, a possible protective role of light alcohol consumption on the development of bladder, kidney and ovarian cancer and Non Hodgkin Lymphoma was observed.”
Forum reviewers found a number of weaknesses in the paper. While their title focuses on “light alcohol drinking,” most of their reports of results and their discussion deal with harmful effects of heavier drinking; however, by not including papers on ‘heavy drinking’ in their original search, they may have left out many relevant papers. Further, the very brief reviews of each common cancer that they comment upon are sometimes based on only one or two meta-analyses, leaving out a huge amount of key data, especially that from single, well-done, long-term cohort studies with important information on the relation of alcohol to cancer; potential confounding by many factors could not be taken into consideration.
In the analyses in the present paper, the reported average level of alcohol consumed is used, but there is insufficient evaluation of possibly more important indices of alcohol exposure: the pattern of drinking (e.g., type of beverage consumed, in binges or on a regular basis, consumption with or without food, etc.). Further, there is probably inadequate control for important confounders or consideration of the effects of under-reporting, which may have been seen in single studies but not apparent in meta-analyses. In addition, a number of errors are present within the report, such as conflicting statements that may misrepresent the numeric data given. These problems make these results of limited use to professionals in health policy who are developing guidelines for alcohol use in the general public.
Reference: Caprio GG, Picascia D, Dallio M, Vitiello PP, Giunta EF, De Falco V, et al. Light Alcohol Drinking and the Risk of Cancer Development: A Controversial Relationship. Reviews on Recent Clinical Trials 2020;15:164-177
For the full critique of this paper by the International Scientific Forum on Alcohol Research, please click here.