by Aditya Mattoo, MD
Not too long ago, a patient came to my clinic and said (I’m paraphrasing of course), “I never cared for alcohol, doctor, so I haven’t had much to drink since my college days. Maybe champagne or wine on the rare special occasion, but I keep hearing about how wine is good for your heart, so I am thinking I should start drinking regularly.”
For years I have been telling patients don’t drink, don’t smoke, don’t do drugs, don’t eat fatty foods, exercise more, and lose weight. I have become quite accustomed to playing the role of “Dr. Buzzkill” with my patients (the actual name given to me by a patient). Yet, we have all heard about the potential benefit to light drinking. Still, I felt a little uneasy about telling someone to start drinking everyday. To ease my discomfort, I decided to review the data behind alcohol and cardiovascular mortality for the current installment of Myths and Realities.
Alcohol and its affects on cardiovascular disease has been studied as far back as 1904, when Dr. Richard Cabot published an article in JAMA attempting to draw a relationship between alcoholism and arteriosclerosis. The recent reemergence of this discussion has been prompted by the observation that French people, although eating a diet relatively rich in saturated fats, had a relatively lower incidence of cardiovascular disease and mortality from cardiovascular events. This so called “French Paradox”, coined in 1992 by Dr. Serge Renaud, a scientist from Bordeaux University in France, has been attributed to the higher consumption of wine.
Several mechanisms for the protective effect of alcohol in cardiovascular disease have been proposed. For example, alcohol related antiatherogenic alterations in plasma lipoproteins, particularly elevations in high-density lipoprotein cholesterol, are thought to offer cardiovascular protection. Additionally, alcohol associated increased activity of endothelial-type nitric oxide synthase, leading to increased levels of nitric oxide and maintenance of blood vessel patency, has also been implicated. Finally, the potential anticoagulant and antiplatelet properties of polyphenols, found in wine, may contribute as well. Some studies have suggested that red wine, because of the disproportionately higher levels of polyphenols as compared to other forms of alcohol (i.e. white wine, liquor and beer), is more protective from a cardiovascular standpoint.
Many clinical studies over the last three decades have attempted to validate this phenomenon. In 1991, Rimm et al published a study of 51,529 male health professionals followed prospectively for two years. A questionnaire was distributed at the beginning of the study asking about alcohol intake in the previous 10 years, along with coronary risk factors, diet, etc. Follow-up questionnaires asked about newly diagnosed coronary disease, and a statistically significant inverse relationship was seen, suggesting a lower incidence of coronary disease in men with increased alcohol consumption.
In 1995, a prospective study of cardiovascular mortality in middle-aged women was published by Fuchs et al. In this study, a dietary questionnaire was sent to 85,709 nurses beginning in 1980 and continuing for a 12 year follow up period. A J-shaped relationship was observed, i.e., light-moderate drinking was associated with a decreased risk of death, however, heavier drinking was associated with an increased risk of death from other causes, particularly breast cancer and cirrhosis.
In 1997, Thun et al published a study following 490,000 men and women for nine years. A similar questionnaire was used to assess alcohol consumption and then cause of death was observed. As one would expect, excessive alcohol consumption was associated with increased rates of death from cirrhosis, as well as cancers of the mouth, esophagus, pharynx, larynx and liver. In contrast, the risk of cardiovascular death was 30-40% lower in both men and women who reported one drink daily compared to nondrinkers.
Castelnuovo et al performed a meta-analysis reviewing 26 studies on the relationship of beer and wine and cardiovascular mortality. Published in 2002, a total of 417,454 persons were studied and a 32% risk reduction of cardiovascular death with moderate wine consumption was observed, whereas a 22% risk reduction was observed with moderate beer consumption.
Finally, in April of this year, the Journal of the American College of Cardiology, published an article by Mukamal et al supporting this growing body of evidence that alcohol consumption prevents cardiovascular disease. Data from the National Health Interview Survey, which surveyed approximately 245,000 U.S. adults annually between the years 1987 and 2000, showed that light and moderate drinkers had a 31% and 38%, respectively, lower risk of death due to heart disease than abstainers.
Overall, large epidemiological findings have consistently demonstrated a cardiovascular benefit of light alcohol consumption. Although no head-to-head prospective studies have been conducted to compare cardiovascular outcomes of different types of alcohol, the literature suggests that red wine seems to be the most protective. However, skeptics note that these studies do not take into account the different drinking patterns of wine, beer and hard liquor drinkers. Another potential confounder is lifestyle. Studies have shown that light, particularly wine, drinkers may have different demographics and behavior patterns as compared to the rest of the population. They have a tendency to eat healthier, exercise more and come from higher socioeconomic backgrounds (which may imply they have better access to medical care). The contribution of the direct effect of alcohol or the common lifestyle choices of light moderate drinkers is a difficult confounder to tease out from survey-based, uncontrolled data.
So bringing it all back home, how should you counsel your patients? Although detractors often complain that the data is largely based on patients answering questionnaires reliably, the literature is has reproduced the benefits of light alcohol consumption time and time again. Furthermore, there is an undeniable paucity of studies that demonstrate light drinking is harmful. Armed with this, Dr. Buzzkill would probably advise patients to have a glass of wine nightly with dinner. Maybe now my patients will start calling me Dr. Feelgood.
Aditya Mattoo is a nephrology fellow and blogs at Clinical Correlations, where this post originally appeared.
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