A case-control study from Newfoundland/Labrador has reported that greater alcohol intake may increase the risk of colorectal cancer (CRC) among obese subjects, but not among non-obese subjects. This is not a particularly large study, and only 45-60% of subjects who were recruited by telephone ended up providing data. Further, it is a case-control comparison, rather than a cohort analysis, making bias in the results more likely.
In this study, there was no relation of alcohol with the risk of CRC when considering the entire population. However, when subjects were stratified by BMI (<30 versus = 30), the data indicate an increase in CRC risk for obese subjects who were "drinkers" (OR=2.2, 95% CI 1.2-4.0), especially among subjects reporting 5 or more drinks/daily (OR=3.7, CI 1.5-9.0). On the other hand, even among obese subjects there was not a clear dose-response effect noted, i.e., there was not a step-wise increase in CRC risk with greater number of drinks/day. For example, the odds ratio (OR) was 2.3 times that of non-drinkers for obese subjects reporting 1-2 drinks/daily and 1.3 for those reporting 3-4 drinks/daily.
It will be interesting to determine if other studies show that there is modification of the association between alcohol intake and colorectal cancer by obesity. If such is the case, it could help understand some of the mechanisms for the development of cancer and provide better guidelines for screening for CRC.
Reference: Zhao J, Zhu Y, Wang PP, et al. Interaction between alcohol drinking and obesity in relation to colorectal cancer risk: a case-control study in Newfoundland and Labrador, Canada. BMC Public Health 2012, 12:94 doi:10.1186/1471-2458-12-94
Comments on this paper were provided by the following members of the International Scientific Forum on Alcohol Research:
Andrew L. Waterhouse, PhD, Marvin Sands Professor, Department of Viticulture and Enology, University of California, Davis; Davis, CA, USA
Harvey Finkel, MD, Hematology/Oncology, Boston University Medical Center, Boston, MA, USA
Tedd Goldfinger, DO, FACC, Desert Cardiology of Tucson Heart Center, Dept. of Cardiology, University of Arizona School of Medicine, Tucson, Arizona, USA
Arne Svilaas, MD, PhD, general practice and lipidology, Oslo University Hospital, Oslo, Norway
R. Curtis Ellison, MD, Section of Preventive Medicine & Epidemiology, Boston University School of Medicine, Boston, MA, USA
Erik Skovenborg, MD, Scandinavian Medical Alcohol Board, Practitioner, Aarhus, Denmark
For the detailed critique of this paper by the International Scientific Forum on Alcohol Research and a listing of references, go to www.bu.edu/alcohol-forum, click on Recent Reports, and select Critique 072 – 23 February 2012, or the link http://www.bu.edu/alcohol-forum/critique-072-obesity-may-modify-the-association-between-alcohol-consumption-and-the-risk-of-colorectal-cancer-23-february-2012/
The specialists who are members of the Forum are happy to respond to questions from Health Editors regarding emerging research on alcohol and health and will offer an independent opinion in context with other research on the subject.
Helena Conibear co Director
The International Scientific Forum on Alcohol Research
helena@alcoholforum4profs.org
Professor R Curtis Ellison co Director
The International Scientific Forum on Alcohol Research
ellison@bu.edu
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