Alcohol and Cardiovascular Disease

Critique 040.  Lower risk of coronary heart disease from alcohol, even with heavy drinking. 27 April 2011

Reference:  Le Strat Y, Gorwood P.  Hazardous drinking is associated with a lower risk of coronary heart disease: Results from a national representative sample.  Am J Addict 2011;20:257–263.

Using data from The 2001–2002 National Epidemiologic Survey on Alcohol and Related Conditions study (the NESARC study, n = 43,093), the authors of this paper conclude that alcohol may have cardioprotective effects not only in moderate drinkers, but also in individuals with patterns of use traditionally considered as “hazardous.”  While such a finding has been shown in some population studies, there were questions by Forum reviewers as to the adequacy of the method for diagnosing coronary artery disease: self-report, with most subjects listing angina pectoris, a “soft” criterion for coronary disease.

In addition, the categories of drinking used in this study were very broad: rare or only occasional drinkers were combined with regular drinkers up to 7 or 14 drinks per week in the “moderate” category; the “hazardous” category included a broad range of drinkers, from a minimal increase over the recommended limits to very heavy drinkers.  The pattern of drinking (especially the number of days per week that alcohol was consumed) was not reported, making it difficult to separate regular from heavy week-end drinkers.  The effects of heavier drinking on other conditions (such as alcohol-related liver disease, mortality, etc.) were not included in this analysis.

It is physiologically possible that even hazardous use of alcohol, like moderate use, may well lead to cleaner arteries and therefore lower rates of coronary artery disease.  If this is the case, an explanation for the increases in cardiovascular mortality reported for heavy drinkers in many studies may relate not directly to coronary artery disease, but to conditions such as cardiomyopathy or cardiac arrhythmias.  However, the rates of accidents, suicide and other morbidity associated with hazardous alcohol use may well overcome any protective effects on coronary disease.

Critique 035.  A review of the association of alcohol consumption with cardiovascular disease outcomes. 5 March 2011

Reference:  Ronksley PE, Brien SE, Turner BJ, Mukamal KJ, Ghali WA.  Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis.  BMJ 2011;342:d671; doi:10.1136/bmj.d671.

In an excellent summary, the authors of this paper have synthesized results from longitudinal cohort studies comparing alcohol drinkers with non-drinkers for the outcomes of overall mortality and mortality from cardiovascular disease (CVD), incident coronary heart disease (CHD), mortality from CHD, incident stroke, and mortality from stroke.  They conclude that light to moderate alcohol consumption is associated with a reduced risk of multiple cardiovascular outcomes.  Further, they suggest that current scientific data satisfy Hill criteria indicating causality, that alcohol intake is the cause of the lower risk of cardiovascular disease among moderate drinkers.

Forum members thought that this was a very well-done, comprehensive summary of a large number of studies on alcohol and cardiovascular disease.  Some believed that two topics were not adequately discussed: (1) greater benefits from wine than from other beverages, a result seen in many studies, and (2) the importance of the pattern of drinking on the health effects of alcohol.  However, Forum members welcomed the discussion in the paper as to causality and regarding future directions in research, with more emphasis into how physicians and individual patients might respond to encouragement to consume alcohol for its potentially beneficial effects on cardiovascular disease.  Most believe that there is no substitute for balanced judgment by a knowledgeable, objective health professional when discussing alcohol intake, and this requires is a synthesis of common sense and the best available scientific facts as they apply to the individual.

Critique 034. A review of interventional studies in humans showing effects of alcohol on risk factors for cardiovascular disease 5 March 2011

Reference:  Brien SE, Ronksley PE,Turner BJ, Mukamal KJ, Ghali WA.  Effect of alcohol consumption on biological markers associated with risk of coronary heart disease: systematic review and meta-analysis of interventional studies.  BMJ 2011;342:d636; doi:10.1136/bmj.d636.

A summary paper on the effects of alcohol consumption on biologic mechanisms associated with coronary heart disease provides an excellent review of a large number of intervention studies in humans.  Appropriate analyses were done and the results are presented in a very clear fashion, although there was little discussion of the separate, independent effects of alcohol and polyphenols on risk factors.

The trials the authors reviewed have demonstrated that the moderate intake of alcoholic beverages leads to increases in HDL-cholesterol, apolipoprotein A1, and adiponectin and decreases in fibrinogen, all factors associated with a lower risk of heart disease.  The findings described in this paper strengthen the case for a causal link between alcohol intake and a reduced risk of coronary heart disease, suggesting that the lower risk of heart disease observed among moderate drinkers is caused by the alcoholic beverage itself, and not by other associated lifestyle factors.

Critique 033. Moderate-to-heavy alcohol intake may increase risk of atrial fibrillation.

12 February 2011

Reference:  Kodama S, Saito K, Tanaka S, Horikawa C, Saito A, Heianza Y, Anasako Y, Nishigaki Y, Yachi Y, Iida KT, Ohashi Y, Yamada N, Sone H.  Alcohol consumption and risk of atrial fibrillation.  A meta-analysis.  J Am Coll Cardiol 2011;57:427–436.

A number of well-done studies have shown an increase in the risk of atrial fibrillation to be associated with heavy alcohol intake or with alcoholism.  Most previous studies suggest little if any increase in risk from light-to-moderate drinking.  The present study was a meta-analysis based on 14 studies from Europe or North America.  It showed an increase in risk with alcohol, but there were limited dose-response data to determine if there was a threshold above which the risk was increased.  Overall, the scientific evidence from many studies suggests that at least heavy drinking may increase the risk of atrial fibrillation, although whether light-to-moderate intake increases the risk seems unlikely.  Previous basic scientific data of mechanisms of atrial fibrillation have suggested that alcohol has little effect on this arrhythmia.

Critique026. Chinese study suggests that alcohol increases angiographically significant   coronary artery disease. 8 December 2010

Reference:  Zhou X, Li C, Xu W, Hong X, Chen J.  Relation of alcohol consumption to angiographically proved coronary artery disease in Chinese men.  Am J Cardiol 2010;106:1101–1103.

Among a large number of Chinese men presenting with chest pain or EKG changes, sequential subjects undergoing cardiac angiography were evaluated for obstructive coronary artery disease (CAD) lesions according to their reported recent alcohol intake.  The study population consisted of 1,476 consecutive men 36 to 84 years of age; participants were categorized as nondrinkers, light drinkers, moderate drinkers, or heavy drinkers.  Adjusted odds ratios for angiographically proved CAD for light, moderate, and heavy drinking were 1.16 (95% confidence interval 0.68 to 1.94), 1.78 (1.35 to 2.27), and 2.18 (1.46 to 3.25).  Compared to non-drinking, adjusted odds ratios were 1.03 (0.54 to 1.87) for drinking 0 to 15 years, 1.61 (1.28 to 2.14) for 16 to 30 years, and 1.98 (1.23 to 3.05) for >30 years.  The authors concluded that moderate-to-heavy alcohol consumption increased the risk of CAD in Chinese men.  CAD risk tended to increase with an increase in frequency and duration of drinking.

This was a very select group of patients (those presenting with chest pain or EKG changes), and not typical of the Chinese population.  No information was available on drinking patterns or on previous alcohol intake.  Further, a recent large population-based study from mainland China showed that consumers of alcohol were less likely to develop coronary disease, results similar to those in most Western populations.  It is not possible from the present study to say that the association of alcohol intake with CAD is different between Chinese and Western populations, as the present study gives results only for a very select group of patients.

The most important outcome regarding CAD is the occurrence of clinical events (myocardial infarction, cardiac death, etc.).  The detection of such events requires long-term follow-up studies to be able to judge the overall effects of alcohol drinking on CAD.

Critique 025.  Pattern of drinking and type of beverage affect the relation of alcohol intake to coronary heart disease 1 December 2010

Reference: Ruidavets J-B, Ducimetièere P, Evans A, Montaye M, Haas B, Bingham A, Yarnell J, Amouyel P, Arveiler D, Kee F, Bongard V, Ferrières J.  Patterns of alcohol consumption and ischaemic heart disease in culturally divergent countries: the Prospective Epidemiological Study of Myocardial Infarction (PRIME).  BMJ 2010;341:c6077 doi:10.1136/bmj.c6077.

Using cohort data from Belfast and France, investigators related weekly alcohol consumption, incidence of binge drinking (alcohol >50 g on at least one day a week), incidence of regular drinking (at least one day a week, and alcohol <50 g if on only one occasion), volume of alcohol intake, frequency of consumption, and types of beverage consumed to risk of coronary heart disease (CHD) events over a 10 year follow-up period.  Overall, 60.5% of subjects from N. Ireland and 90.6% of French reported drinking alcohol at least once a week.  Among drinkers, 12% of men in Belfast drank alcohol every day compared with 75% of men in France.  Mean alcohol consumption was 22.1 g/ day in Belfast and 32.8 g/day in France.  Binge drinkers comprised 9.4% and 0.5% of the Belfast and France samples, respectively.

Results showed that, after multivariate adjustment, the hazard ratio for hard coronary events compared with regular drinkers was 1.97 (95% CI 1.21 – 3.22) for binge drinkers, 2.03 (95% CI 1.41 – 2.94) for never drinkers, and 1.57 (95% CI 1.11 – 2.21) for former drinkers.  The hazard ratio for hard coronary events in Belfast compared with in France was 1.76 (95% CI 1.37 to 2.67) before adjustment, and 1.09 (95% CI 0.79 to 1.50) after adjustment for alcohol patterns and wine drinking.  Only wine drinking was associated with a lower risk of hard coronary events, irrespective of the country.

The authors conclude that regular and moderate alcohol intake throughout the week, the typical pattern in middle-aged men in France, is associated with a low risk of ischemic heart disease, whereas the binge drinking pattern more prevalent in Belfast confers a higher risk.  While a strong inverse association between moderate alcohol consumption and cardiovascular disease has been demonstrated for decades, more recent research has emphasized the importance of the pattern of drinking (regular moderate versus episodic or binge drinking).  Further, there continues to be debate about the potential greater effect of wine versus other beverages containing alcohol.  This study shows that regular moderate drinking (especially of wine) is associated with lower risk of MI, but episodic or binge drinking (especially of beer or whiskey) increases the risk.  Lifetime abstinence has a similar adverse relation to CHD as does episodic or binge drinking.

Critique 010. Should moderate alcohol consumption be advised following a heart attack? 30 June 2010

Reference:  Carter MD, Lee JH, Buchanan DM, Peterson ED, Tang F, Reid KJ, Spertus JA, Valtos J, O’Keefe JH.  Comparison of outcomes among moderate alcohol drinkers before acute myocardial infarction to effect of continued versus discontinuing alcohol intake after the infarct.  Am J Cardiol 2010 (Published early online).

There has been considerable recent interest in the effects of alcohol consumption following an acute myocardial infarction (AMI).  In an observational study among 325 subjects who were moderate drinkers prior to an AMI, 84% continued to drink and 16% quit.  While most of the outcome measures showed no statistically significant effects between the two groups of patients, all outcomes showed a tendency towards better physical and mental health outcomes for persistent drinkers in comparison with those who quit drinking.

A key problem with this analysis, and with all observational epidemiologic studies on this topic, is that the reason that some subjects stopped drinking after having an AMI, while others continued to drink, is not known.  Even though adjustments were made for many known related factors, there is always the possibility that subjects who stopped drinking were “sicker” in many ways than those who persisted in their alcohol consumption.

It may well require a randomized trial, in which some subjects having an AMI are randomly advised to continue to drink and others advised to stop drinking, to be able to determine reliably the effects on the clinical course of the persistence of alcohol intake following an AMI.

Critique 006. For patients who already have cardiovascular disease, continued moderate alcohol consumption may reduce their risk of death 2 June 2010

Reference:  Costanzo S, Di Castelnuovo A, Donati MB, Iacoviello L, de Gaetano G.  Contemporary Reviews in Cardiovascular Medicine.   Cardiovascular and overall mortality risk in relation to alcohol consumption in patients with cardiovascular disease.  Circulation 2010;121;1951-1959.

This review paper in Circuation summarizes data from 8 epidemiologic studies of subjects with cardiovascular disease (CVD) as to their subsequent mortality (both CV and total-mortality) according to their alcohol consumption.  Most studies showed significantly lower risk of both CV and total mortality for patients with CVD who were consumers of alcohol.

Despite these clear-cut findings, the authors were very cautious in their conclusions, focusing on the dangers of excessive drinking and not encouraging cardiovascular patients who do not drink to start regular drinking.   They state that moderate consumers of alcohol who have CV disease should not be advised to stop drinking, but should be advised to not consume alcohol more heavily.

It is interesting that these authors published the meta-analysis upon which this review is largely based in the Journal of the American College of Cardiology earlier in 2010.  In that paper, their conclusions were less restrained: “Cardiologists should be aware that regular, moderate alcohol consumption, in the context of a healthy lifestyle (increased physical activity, no smoking), dietary habits (decreased dietary fat intake, high consumption of fruit and vegetables), and adequate drug therapy, would put their patients at a level of cardiovascular or mortality risk substantially lower than either abstainers or heavy or binge drinkers.”

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