Alcohol consumption has not only been shown to decrease the risk of mortality, but it also seems to decrease the risk of developing coronary artery disease (CAD). Yano et al. followed 7,705 Hawaiian males of Japanese descent for six years and found a RR in CAD with moderate alcohol intake (mainly beer). This relationship held after control for other risk factors.17
Camargo et al. studied 22,071 U.S. male physicians and found that moderate alcohol drinkers had a 0.69 RR in developing angina and a 0.65 RR of developing a myocardial infarction.18 Another study also showed that moderate drinkers (7-13 drinks/week) with previous coronary artery bypass surgery (CABG) had a 30% decrease in clinical events compared to CABG patients who drank less alcohol (1-6 drinks/week). Presumably there was a favorable effect in reducing the progression of the CAD.19
Alcohol consumption has been shown to improve the prognosis in patients after an acute myocardial infarction (AMI). Mukamal et al. examined all cause mortality following an AMI to evaluate the effect of alcohol intake in the year before the acute event. They found that moderate alcohol consumption reduced the mortality following an AMI.20 The same investigators looked at female survivors of AMI and found the same relationship between favorable prognosis and moderate alcohol intake.21 However, these authors did find that binge drinking (three or more drinks over one to two hours) after AMI was associated with a doubling of mortality while moderate intake was associated with reduced mortality.22
The data suggests that patients with moderate daily alcohol intake have a decreased risk of developing CAD. Patients with CAD and moderate alcohol intake have a decreased risk of complications from CAD compared to the CAD patients who do not drink alcohol.
It is known that patients with diabetes mellitus (DM) have an increased risk of CVD and thus are a very high risk subset. In a review of 32 studies on the effects of alcohol on diabetes mellitus Howard et al. found that moderate alcohol intake (1-3 drinks/day) reduced the incidence of DM by 33 to 56%. In the same study they found a lower incidence (34 to 55%) of CAD in the diabetic patients who consumed alcohol in moderation. However heavy consumption (>3 drinks/day) was associated with a 43% increase in the incidence of DM.23 In the Health Professional Follow-up Study (HPFS) 2,419 men over age 30 with Type 2 DM were followed for the development CAD. There was a reduction in the risk of CAD with alcohol consumption (0.5-2 drinks/day).24
Valmadrid et al. followed 983 older adults with type 2 DM (mean age 68.6 years) for 12.3 years. They found in patients who never drank or were former drinkers a CHD mortality of about 40 per 1,000 patient years. In the persons consuming 14 or more g/day the CAD mortality was 10 per 1,000 patient year. 25
Koppes et al. performed a meta-analysis of 15 prospective cohort studies showed that moderate alcohol consumption (1-2 drinks/day) was associated with a 30% decrease in the risk of developing DM. They did find a J-shaped relationship between alcohol consumption and the risk of developing DM.26
Another meta-analysis examined the relationship between alcohol consumption and the prevalence of the metabolic syndrome (MS). They found that consumption of < 40 g/day in men and < 20 g/day in women was associated with a reduced prevalence of MS when compared with the control group who abstained from alcohol intake.27
Gigleux et al. evaluated 1,966 men from the Quebec Cardiovascular Study. All of the men were free of CAD at baseline and they were followed for 13 years. They found that men who drank ≥ 15.2 g/day of alcohol had a 40% decrease in the risk of developing MS compared to non-drinkers. The men with MS had a 39% reduction in the risk of CAD if they consumed ≥15.2 g/day.28
In summary these studies show a beneficial effect of moderate alcohol intake on the development of diabetes as well as the MS. In addition in the patients with diabetes who consume moderate alcohol there is a reduction in CAD as well as cardiovascular complications.
Alcohol abuse has been associated with a dilated cardiomyopathy. Drinking > 90 grams of alcohol per day for an extended period has a causal relationship with an alcoholic cardiomyopathy.29 The angiotensin converting enzyme DD genotype has been associated with a predisposition for the development of an alcoholic cardiomyopathy.30
However studies have also shown that moderate alcohol intake is associated with decreased risk of developing heart failure (HF) and improvement in heart failure symptoms. The Physicians Health Study involving 21,601 male physicians showed that healthy physicians who had moderate daily alcohol intake had a risk reduction of 0.62 of developing HF over 23 years of follow-up.31 The Cardiovascular Health Study is a prospective cohort study of 5888 patients ≥ the age of 65. These patients were followed for 7-10 years and in that time the risk of developing HF was 0.66 lower in moderate drinkers (1-2 drinks/day) when compared to non-drinkers. The difference was not totally due to the lowered incidence of AMI.32 Abramson et al. studied 2,235 elderly citizens who were free of heart failure at baseline (mean age 73.7 years). They found that moderate alcohol consumption was associated with a decrease risk of HF and again the reduction did not appear to be totally related to the incidence of AMI33. Likewise the Framingham Heart Study reported similarly that moderate alcohol consumption was associated with decreased HF.34
The SOLVD trial evaluated 3,719 non-drinking patients and compared them to 2,594 patients who drank 1-14/week (light to moderate drinkers). All the participants had an ejection fraction ≤ 35%. They found that light to moderate drinkers had a mortality rate of 7.2/100 patient years compared with 9.4/100 patient years for non-drinkers. They found that this amount of alcohol consumption had no effect on the mortality in patients with a non-ischemic cardiomyopathy. This suggests that the mortality benefit in this study could be due to alcohol reducing cardiac events in the CAD patients.35
The SAVE trial studied 2,231 patients with an ejection fraction < 40% after AMI. The patients were grouped by the alcohol consumption into nondrinkers, light to moderate (1-10 drinks/week) and heavy (>10 drinks/week). All groups had the same risk of developing HF or receiving open label ACE-inhibitor. Neither benefit nor excess harm was found in those who drank alcohol although there were only a small number of patients (235) who drank > 10 drinks/week.36
Klatsky et al. evaluated 126,235 members from the Kaiser Permanente Medical Care Program to examine the effect of alcohol use on the development of HF. They found the RR of HF was directly related to the number of drinks/day in participants without CAD and inversely proportional in members with CAD. The detrimental effect of alcohol in the non-CAD group was seen with a consumption of ≥ 3 drinks/day. This data suggest that alcohol in high amounts is harmful in patients without CAD and exerts a beneficial effect in patients with CAD.37
Nicolas evaluated the effects of reduced drinking in a group of 55 alcoholic men with alcoholic cardiomyopathy who had been drinking at least 100 grams/daily of alcohol for a minimum of ten years. They followed serial echocardiograms or radionuclide angiograms in these men. They found deterioration in those who continued to consume >80 grams/daily of alcohol but interestingly there was improvement in left ventricular function in both the group that abstained from alcohol as well as those who reduced the consumption to 20-60 g/day.38
In summary, the studies cited here show no harmful effect of from alcohol use except in high doses in patients without CAD. Based on the available evidence it is likely that moderate alcohol use has a favorable effect to reduce the incidence of heart failure although the mechanism of the benefit is not clear but may in some patients work by lowering coronary events.
Alcohol intake has been associated with hypertension and the JNC 7 report recommends no more than two alcoholic drinks in men and no more than one drink in women.39 As a result of this association the relationship between alcohol intake and stroke risk has been extensively studied. Reynolds et al. performed meta-analysis examining alcohol consumption and the risk of stroke, both ischemic and hemorrhagic. Consumption of more than 60 g/day was associated with an increase in both ischemic and hemorrhagic stroke. An intake of less than 12 g/day was associated with a reduced stroke rate. The authors felt that light to moderate alcohol intake had a protective effect for stroke.40
The Physicians’ Health Study had 14,125 men who had a history of hypertension but were free of stroke, MI, cancer or liver disease at baseline. The alcohol intake was self-reported by these physicians. They found a protective effect for CVD mortality in these hypertensive physicians who reported light to moderate alcohol consumption.41
In a study of 38,156 of male health professionals the risk of stroke was assessed in relationship to the alcohol intake. The consumption was found to be < 1 drink/day (light), moderate (1-2 drinks/day) or heavy (≥ 3 drinks/day). They did determine the type of alcohol consumed as beer, wine or liquor and there was a 14-year follow-up period. They found no increase risk of stroke with drinking ≤ 2 drinks/day but with drinking >2 drinks per day the stroke rate increased. Red wine consumption lowered the risk but liquor or beer did not reduce the risk.42 Stampfer et al studied 87,526 female nurses for the risk of CAD and stroke as it related to alcohol consumption. The age at the onset of the study ranged from 34 to 59 years. The authors found that moderate alcohol consumption decreased the risk of CAD and ischemic stroke.43 In summary, light to moderate alcohol was found to reduce the risk of stroke in three of four studies and alcohol in excess was detrimental.
The association with binge drinking and atrial fibrillation (AF) was termed “Holiday Heart Syndrome” by Ettinger et al. 44 Frost looked at the association between atrial fibrillation or flutter and alcohol consumption in the Danish Diet, Cancer, and Health Study among 47,949 participants with a mean age of 56 years. The mean consumption in men was 28.2 ± 25g and in women it was 13.9 ± 15 g. Compared to the lowest quintile of alcohol consumption, the highest quintile had a 1.46 hazard rate ratio. In contrast there was no association of the arrhythmias with moderate alcohol consumption in women.45
The Copenhagen City Heart Study had 16,415 participants. They found an association of AF in men who consumed ≥ 35 drinks/week. They did not find the association in women but only a very small number consumed this much alcohol.46 Kodama et al. performed a meta-analysis of 14 studies to examine the effect of alcohol consumption on AF. They found that the lowest risk of AF was with no alcohol consumed and there was an increasing risk of AF with increased consumption of alcohol.47
Thus it appears that alcohol in excess increases the risk of AF and there is no level of use that reduces the risk.
A high intake of red wine by the French has been postulated to explain a reduced risk of CVD in France despite a high fat diet (the French Paradox). However a study of 38,077 male health professionals found that drinking < 10g/day to ≥ 30 g/day had a reduced incidence of myocardial infarction. The benefit was independent of the type of alcohol consumed.48 In this same study group these investigators did find that red wine consumption had a more favorable effect for reduction in ischemic stroke risk. 42 Moderate beer or wine drinking was associated with lower levels of systemic inflammatory markers.49 In the study of Yano et al. beer had a favorable effect on non-fatal MI and CHD death.17
At this time there is no definite data that any of the forms of alcohol are more protective than the others.
The purpose of this review is to summarize the data on alcohol consumption and its effect on the cardiovascular system. We hope this summary will be helpful for physicians to make evidence-based recommendations to their patients regarding alcohol use.
Most studies have found a J-shaped relationship between alcohol consumption and health benefits. Moderate daily alcohol use (1 drink/day in women and 1-2 drinks/day in men) has been shown to provide the most benefit. Greater than three drinks per day has been associated with increased morbidity and mortality except for men with CAD in which there is still a benefit with three drinks/day. Binge drinking does not provide the same benefit as moderate daily intake. There is no data supporting one type of alcohol over another. The most important aspect appears to be amount and pattern of alcohol intake.
Moderate alcohol intake has been found to be beneficial in reducing the risk of all cause mortality in addition to cardiovascular mortality and cardiovascular morbidity. Clinicians should not discourage healthy patients nor patients with cardiovascular disease from moderate daily alcohol intake unless they have obvious contraindications. These contraindications include atrial arrhythmias, liver disease, gastritis, alcoholism, family history of alcoholism, other substance abuse issues and psychiatric illnesses.
Patients with excessive alcohol use should be counseled to reduce their drinking to moderate daily intake (1-2 drinks/day). Physicians should not counsel patients to start drinking alcohol if they currently abstain. At this time there are no randomized controlled trials (RCT) to evaluate the initiation of alcohol as a therapeutic agent. It is unlikely that any RCT will be done on alcohol consumption.
As with any recommendation, it is important to weigh the risks and benefits for each patient before counseling on alcohol consumption. However, it appears that there is abundant evidence supporting the use of moderate daily alcohol intake to reduce the risk of cardiovascular complications. Therefore, we believe that it is safe for you and your patients to “Toast to Health” but imbibe in moderation.
The researchers, led by Dr. Gemma Chiva-Blanch of the University of Barcelona, Spain, conclude that the polyphenols found in red wine are the likely mediators of the blood-pressure reduction and that alcohol appears to weaken their antihypertensive effect.a
They suggest that daily consumption of nonalcoholic red wine may be useful for the prevention of mild to moderate hypertension.
For the study, published online in Circulation Research on September 6, 2012, 67 men at high cardiovascular risk were randomized into three four-week treatment periods in a crossover clinical trial. Each participant followed a common background diet and also drank red wine (30 g alcohol/day), the equivalent amount of dealcoholized red wine, or gin (30 g alcohol/day). Blood pressure and plasma nitric-oxide (NO) concentration were measured at baseline and between each intervention. The men were moderate alcohol consumers before the study, but they abstained from drinking any alcohol for a two-week run-in period at the start of the study.
Results showed that both systolic and diastolic blood pressure decreased significantly after the dealcoholized red wine intervention, and these changes correlated with increases in plasma NO. During the red-wine phase, the men had a small reduction in blood pressure and a small increase in NO, while there was no change in blood pressure and a small reduction in NO while drinking gin.
The researchers note that although the blood-pressure reduction associated with nonalcoholic red wine was modest, reductions of this magnitude have been associated with a 14% decrease in coronary heart disease and 20% reduction in stroke risk.
Changes in Blood Pressure and Nitric Oxide with the Different Beverages
Change in BP/NO Red wine Nonalcoholic Red Wine Gin
Systolic blood pressure (mm Hg) -2.3 -5.8 -0.8
Diastolic blood pressure (mm Hg) -1.0 -2.3 -0.1
Nitric oxide (µmol/L) +0.6 +4.1 -1.4
Douglas B. Bogart, MD, MSMA member since 1978, is recently retired Associate Professor of Medicine and Section Chief of Cardiology at Truman Medical Center and Missouri Medicine Editorial Board member. Christopher Griffith is a sixth year medical student at the University of Missouri - Kansas City.
Editor's note: This article is part of a special series brought to you by Missouri Medicine, the Medical Journal of the Missouri State Medical Association (MSMA). MedHelp, Missouri Medicine, and MSMA are collaborating to educate and empower health consumers by making the latest scientific studies and medical research available to the public. Learn more about MSMA and see more from Missouri Medicine.
This article was originally published in the Nov/Dec 2012 issue of Missouri Medicine.
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