By William B. Ershler, MD, INOVA Fairfax Hospital Cancer Center, Fairfax, VA; Director, Institute for Advanced Studies in Aging, Washington, DC. Dr. Ershler reports no financial relationships relevant to this field of study.
Synopsis: There has been much written about the salutary effects of moderate alcohol consumption in reference to a number of non-malignant chronic diseases. The effects on cancer in general are less compelling. However, in the current meta-analysis examining alcohol consumption and the development of renal cell carcinoma, a protective effect for light and moderate drinkers is clearly demonstrated. This protective effect is in the 10-20% range.
Source: Bellocco R, et al. Alcohol drinking and risk of renal cell carcinoma: Results of a meta-analysis. Ann Oncology 2012;23:2235-2244.
There has been a gradual increase in renal cell carcinoma (RCC) in the United States and slightly improved survival, both of which may relate to earlier detection.1,2 There are well-established risk factors for RCC including tobacco smoking,3 obesity,4 and hypertension,5 but there remains some controversy over the role of moderate or excessive alcohol intake in this context. In fact, in a pooled analysis on alcohol intake and RCC based on 12 cohort studies, moderate consumption of alcohol was inversely related to the risk of RCC, and such protection did not seem to be modified by age, body mass index, hypertension, or smoking.6 That analysis, however, did not address the issue of high levels of alcohol intake. To address this, Bellocco and colleagues conducted a comprehensive meta-analysis of published studies on this topic.
The investigators were able to find 20 observational studies (four cohort, one pooled, and 15 case-control) published up to November 2010 that reported results on at least three levels of alcohol consumption in the context of RCC incidence. Overall relative risks (RRs) and 95% confidence intervals (CIs) were estimated using random-effects models, and both second-order fractional polynomials and random effect meta-regression models were implemented for the study of dose-risk relation.
They found the estimated RRs were 0.85 (95% CI, 0.80-0.92) for any alcohol drinking, 0.90 (95% CI, 0.83-0.97) for light drinking (0.01-12.49 g/day), 0.79 (95% CI, 0.71-0.88) for moderate drinking (12.5-49.9 g/day), and 0.89 (95% CI, 0.58-1.39) for heavy drinking (≥ 50 g/day), respectively.
Thus, the current meta-analysis supports the hypothesis of a negative effect of moderate alcohol consumption on the risk of renal cell cancer. In this analysis, special efforts were undertaken to address the interactions of smoking and obesity, both of which are highly associated with excessive alcohol intake. Thus, the protective effect of alcohol on RCC development might be countered by associated factors. Furthermore, heavy drinkers are more likely to have a poor diet, and this too would favor RCC development.7 As such, this report provides epidemiological evidence that light or moderate alcohol consumption is associated with a reduced risk (10-20%) of RCC, and that such is observed independent of tobacco use, body mass index, or presence of hypertension.
The mechanism whereby alcohol would confer such an effect is conjectural at this time but, at least for red wine, may relate to the beneficial metabolic effects conferred by resveratrol.8 However, there is now a growing literature supporting the positive effects of low or moderate alcohol intake on such diverse processes as diabetes,9 cardiac disease,10 and Alzheimer's,11 as well as normal aging and overall mortality.12,13
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