Critique 062: Similar effects of beer and wine on the risk of cardiovascular disease and of total mortality ———- 22 November 2011

Costanzo S, Di Castelnuovo A, Donati MB, Iacoviello L, de Gaetano G. Wine, beer or spirit drinking in relation to fatal and non-fatal cardiovascular events: a meta-analysisEur J Epidemiol 2011;DOI 10.1007/s10654-011-9631-0

Authors’ Abstract

In previous studies evaluating whether different alcoholic beverages would protect against cardiovascular disease, a J-shaped relationship for increasing wine consumption and vascular risk was found; however a similar association for beer or spirits could not be established.

An updated meta-analysis on the relationship between wine, beer or spirit consumption and vascular events was performed.  Articles were retrieved through March 2011 by PubMed and EMBASE search and a weighed least-squares regression analysis pooled data derived from studies that gave quantitative estimation of the vascular risk associated with the alcoholic beverages.

From 16 studies, evidence confirms a J-shaped relationship between wine intake and vascular risk.  A significant maximal protection — average 31% (95% confidence interval (CI): 19–42%) was observed at 21 g/day of alcohol.  Similarly, from 13 studies a J-shaped relationship was apparent for beer (maximal protection: 42% (95% CI: 19–58%) at 43 g/day of alcohol).  From 12 studies reporting separate data on wine or beer consumption, two closely overlapping dose–response curves were obtained (maximal protection of 33% at 25 g/day of alcohol).

This meta-analysis confirms the J-shaped association between wine consumption and vascular risk and provides, for the first time, evidence for a similar relationship between beer and vascular risk.  In the meta-analysis of 10 studies on spirit consumption and vascular risk, no J-shaped relationship could be found.

Forum Comments

Background:  As pointed out by the authors, there have been numerous observational cohort studies indicating a lower risk of cardiovascular disease associated with moderate alcohol intake.  While many studies suggest that individuals reporting wine consumption tend to have better health outcomes than consumers of other beverages, other studies do not show significant differences according to type of beverage reported.

Comments on present paper:  The authors carried out an updated meta-analysis to determine if there are differences in the association between beer, wine, and spirits with fatal and non-fatal cardiovascular events.  The analyses are well-done and based on state- of-the-art statistical techniques.

A major problem with all meta-analyses is the inability to control for variables that were not included in the original reports.  While there were adequate data to adjust for most of the usual confounders, there was no way to evaluate effects of the pattern of drinking (frequency, binge drinking, etc.) on the cardiovascular outcomes.

Their analyses describe very similar J-shaped associations for wine and for beer with these health outcomes.  In the best fitting models among studies of vascular risk that reported data on both wine and beer consumption, vascular risk was reduced by more than 30% for both beverages; the reversion point for wine was 70 g/day and for beer 43 grams/day.

Limited data were available about the association of spirits intake and cardiovascular risk.  While the trend was for a decrease in such risk with increasing spirits consumption, there was not a statistically significant relation in the meta-analysis based on 10 independent relationships  using random models.

The key finding of this meta-analysis was the similar inverse  association between the consumption of beer and wine and cardiovascular disease.  The lack of a similar J-shaped association for spirits may be due to different drinking patterns according to type of beverage.  Hence, it is not possible to infer from these analyses that polyphenols present in beer and wine underlie the beverage-specific differences.  Further, the results do not necessarily indicate that the alcohol in each beverage is, or is not, the most important factor associated with  cardiovascular outcomes.  In any case, as concluded by the authors, this meta-analysis provides further evidence for a significant J-shaped inverse association for both wine and beer in relation to vascular risk.

Forum Summary

The authors carried out an updated meta-analysis on the relationship between wine, beer or spirit consumption and cardiovascular outcomes, using state-of-the-art statistical techniques.  Their meta-analysis provides evidence of J-shaped relationships between both wine and beer intake and vascular risk, with maximal protection of about 33% at a level of 25 g/day of alcohol (approximately 2 drinks/day by US standards).  A statistically significant association between spirits intake and vascular disease was not found.

The key result of this meta-analysis is the finding of a very similar inverse association between the consumption of beer and the consumption of wine in relation to cardiovascular outcomes.  While a similar association was not seen for spirits consumption, the data presented do not permit the conclusion that the key effects on cardiovascular disease are primarily due to the polyphenols in beer and wine.  Similarly, the results do not permit the conclusion that the effect on cardiovascular disease is due primarily to the alcohol in these beverages.  The lack of a similar J-shaped association for spirits may have been due to different drinking patterns (e.g., more binge drinking among consumers of spirits), as the pattern of drinking was not included as a confounder in the analyses.

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Comments on this critique by the International Scientific Forum on Alcohol Research were provided by the following members:

Ross McCormick, PhD, MSc, MBChB, Associate Dean, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand

Arne Svilaas, MD, PhD, general practice and lipidology, Oslo University Hospital, Oslo, Norway

David Vauzour, PhD, Senior Research Associate, Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, UK

Andrew L. Waterhouse, PhD, Marvin Sands Professor, Department of Viticulture and Enology, University of California, Davis.

Yuqing Zhang, MD, DSc, Clinical Epidemiology, Boston University School of Medicine, Boston, MA, USA

R. Curtis Ellison, MD, Section of Preventive Medicine/Epidemiology, Boston University School of Medicine, Boston, MA, USA