Critique 069: Little effect of binge drinking on heart disease or mortality among moderate drinkers in Denmark — 2 February 2012

Skov-Ettrup LS, Eliasen M, Ekholm O, Grønbaek M, Tolstrup JS.  Binge drinking, drinking frequency, and risk of ischaemic heart disease: A population-based cohort study.  Scandinavian Journal of Public Health 2011;39:880–887.

Authors’ Abstract

Introduction:  Light-to-moderate alcohol drinking is associated with a decreased risk of ischaemic heart disease (IHD).  However, drinking heavily and in binges has been suggested to increase IHD risk.  This complexity makes the issue of binge drinking within the light-to-moderate alcohol range an important area for further investigation.

Methods:  This population-based cohort study included 26,786 men and women who participated in the Danish National Cohort Study in 1994, 2000, and 2005.  Binge drinking (defined45 drinks/day) and risk of IHD and all-cause mortality was investigated among light-to-moderate drinkers (defined ≤ 21 and ≤ 14 drinks/week for men and women, respectively).  In the entire study population, we investigated the association between drinking frequency, separately and combined with total weekly alcohol intake, and risk of IHD and all-cause mortality.

Results:  1,136 individuals developed IHD during a mean follow up of 6.9 years.  Among male light-to-moderate drinkers reporting occasional binge drinking, the hazard ratio (HR) of IHD was 0.81 (95% CI 0.61–1.08) compared to male light-to-moderate drinkers reporting no binge drinking.  Corresponding HR for women was 0.97 (95% CI 0.54–1.76).  For women drinking 5–6 days/week, the risk of IHD was lower than for women drinking 1–2 days/week (HR 0.54, 95% CI 0.32–0.90).  We did not observe any patterns when looking at combinations of total weekly alcohol intake and drinking frequency.

Conclusions: Among light-to-moderate alcohol drinkers, binge drinking was not associated with risk of IHD and all-cause mortality.  Overall, drinking frequency did not appear to be an important determinant of the risk of IHD and all-cause mortality.

Forum Comments

Most observational epidemiologic studies have found that binge drinking is associated with a loss of alcohol’s protective effect against ischemic heart disease (IHD), with some studies finding an increase in risk among binge drinkers.  This study from Denmark sought to determine if binge drinking related to IHD or all-cause mortality among what they define as “light-to-moderate” drinkers: up to 21 drinks/week for men and up to 14 drinks/week for women.  A “drink” was considered to contain approximately 12 grams of alcohol.

Comments on study:  This appears to be a well-done population–based study with good follow up and excellent ascertainment of outcomes: IHD and all-cause mortality.  This was made possible by the unique civil registry number allocated to each Danish citizen at birth.  This number is used in any sort of business with the authorities such as tax, social security, and health, and a social security card with the number must be presented with any contact with the national health system – a failsafe method of securing exact follow-up of all diagnoses or death.

The assessments of alcohol were based on consumption in the week prior to the examination, and binge drinking was defined as more than 5 drinks/occasion.  Given that the assessment was from only one week, data were not available to judge whether or not binge-drinking episodes occurred rarely or regularly. 

Data were available on the usual covariates related to IHD: smoking, education, physical activity, BMI, and self-reported hypertension and diabetes.  There was a strong correlation between binge drinking and the total amount of alcohol consumed, but the authors controlled for total alcohol intake when comparing binge and non-binge drinkers.

When comparing outcomes in binge vs. non-binge drinkers, the analyses were restricted to subjects in the “light-to-moderate” categories.  Here, there were no significant differences noted between subjects who binged and those who did not.  In all comparisons, the relative risk of IHD and all-cause mortality was higher for non-drinkers than for all categories of drinkers.

When relating frequency of drinking (the number of days of the week when subjects consumed alcohol) to IHD and total mortality, all subjects (not just the light-to-moderate drinkers) were included.  Here, again, there were no significant differences in outcomes comparing people consuming alcohol on 1-2, 3-4, 5-6, or 7 days/week (although , once again, the highest risk was always among the non-drinkers).  These results differ from those of Mukamal et al¹ and Tolstrup et al,² studies showing that frequency of consumption was a key determinant of health outcomes.

Thus, these findings do not show differences in effects of binge vs. non-binge drinking in terms of IHD or mortality.  Further, the study does not show a significant effect according to the number of days per week that subjects consumed alcohol.  As one reviewer stated: “The present paper suggests that, within the group of persons following sensible drinking limits of weekly amount of alcohol intake, there does not appear to be adverse effects on the heart when not following the recommendation to avoid having more than five drinks on a single occasion.”

Specific comments on the results of the present study:  As a Forum reviewer commented: “The sensible drinking limits of up to 21 drinks/week for men or up to 14 drinks/week for women (1 drink = 12 grams of alcohol) proposed by the Danish National Board of Health are well known in Denmark.  It is estimated that, overall, 20% of the population over 16 years of age drink in excess of the proposed drinking limits.³  However, by limiting the study of the effect of binge drinking to subjects who follow the weekly drinking limits (83.7% of the male and 90.4% of the female participants), you have restricted the analysis of binge drinking effects to a population of genuine moderate drinkers.”  If binge drinking among all drinkers were evaluated, the results may well have been different. 

In the present analyses, a very high percentage of the “light-to-moderate drinkers” reported binge drinking: up to 61% of men in the 14-21 drinks/week category and 35% of the women in the 7-14 drinks/week category.  The median number of drinks on a binge was 9 for men and 7 for women.  Despite reporting binge drinking, the overall average intake of the subjects in these analyses remained in the light-to-moderate category.  Hence, although they reported binge drinking on at least one occasion in the preceding week, they were not overall heavy drinkers. 

As one reviewer commented, “The combination of moderate drinking with occasional parties with intake of >5 drinks is a normal pattern of drinking in Denmark.  It is assumed that many were in the habit of sharing some bottles of wine with friends on a Saturday evening and then drink very little during work days, while others prefer the daily glass of wine or beer with their meals.  However, they would be very similar in other choices of lifestyle.”  While the type of beverage consumed was not reported in this paper, a reviewer comments: “Based on data from earlier reports from the Danish National Cohort Study. you would expect that most of the female participants are wine drinkers and that many of the moderate male consumers also prefer wine.”  Previous studies from Copenhagen have shown better health outcomes for wine drinkers than for consumers of other beverages.⁴  In this study, non-drinkers tended to have lower levels of education than the moderate drinkers, as has been found commonly in other studies..

Forum comments on “binge drinking” and health outcomes:  The results of this study appear to be at odds with some previous reports.  For example, Mukamal et al⁵ showed that the risk of myocardial infarction was lower for moderate drinkers than for abstainers, but that subjects reporting binge drinking lost such a putative protective effect.  Some of the differences between the results of the present study and some earlier ones may reflect problems that scientists have when defining “binge drinking.”  Investigators at Harvard have suggested that the rate at which alcohol is consumed (such as the consumption of 3 or more drinks within 1 to 2 hours), rather than the total amount consumed, may be a better definition of binge drinking.  Drinking over several hours while consuming food will surely have different effects than the rapid consumption of similar amounts of alcohol on an empty stomach. 

One Forum reviewer suggested that the circumstances of consumption may play a major role in the health effects.  He considered the concept that just counting up the number of drinks on an occasion in not adequate to diagnose binge drinking.  He challenged the Forum reviewers to consider the following: ”Ask yourself how many drinks you might often consume during an evening with friends, starting with a glass or two of sparkling wine, some glasses of white wine with the fish and a glass or two of red wine with the meat, and even perhaps a sweet dessert wine and maybe a tiny glass of brandy with your coffee.  Count these up, and many of you might agree with a paraphrase of a famous Pogo quote by Walt Kelly: “We have met the binge drinker, and he is us.”  Another reviewer adds: “My personal reaction is that true light-to-moderate drinkers consume, say, one drink daily with dinner on most days, but every now and then join friends for a gala multiple-course (and multiple-drink) meal. Is this the abusive binge drinker we need be concerned with? I think not.”

How to define “sensible drinking”:  A European Forum member stated: “The general accepted limit of no more than 2 drinks/day for men and 1 for women may be overly conservative, especially for IHD and in European adults.”  Said another reviewer, “It is possible that in this selected population with a relatively small overall intake of alcohol (‘genuine moderate drinkers’), the category of binge drinkers was simply a proxy for subjects with a higher amount of alcohol intake, but still within a range of  alcohol that is protective. The paper states that the mean intake was 2 drinks/day for subjects with a binge pattern and 1 drink/day for non binge drinkers.  Although the authors provided analysis adjusted for total alcohol intake, this fact may at least in part explain their findings.”

Another Forum reviewer points out that the term binge drinking “is inconsistently defined in the literature and the definition is hence quite arbitrary.  In Australia, previous alcohol drinking guidelines ‘permitted’ the occasional up to 6 standard drinks per day for men and 4 for women as not being particularly harmful; the current guideline has dropped that to 4 and 4.  Further, the definition of a standard drink varies widely between countries as well, between 8 and 14 g at least, which also needs to be considered.”  Referring to the “J-shaped curve,” an American reviewer stated: “Many meta-analyses suggest that the risks of coronary disease and total mortality remain lower than those of non-drinkers extending out to 5 to 6 drinks/day,^6-8 a level that most, if not all, would consider excessive.  This is not often reported, as it is countered by a propensity to adverse health effects, and more importantly, is not politically correct.”

The Forum does not take the results of this single study to support binge drinking.  What the Danish results suggest is that the occasional “dinner-binge” embedded in a moderate consumption pattern is not harmful.  As stated in the Guide to Sensible Drinking from the UK in 1995, occasional episodes of consumption greater than the recommended levels do not necessarily change the classification of a normally moderate drinker into that of an abuser.⁹ 

References for Forum review:

1.  Mukamal KJ, Conigrave KM, Mittleman MA, Camargo CAJ, Stampfer MJ, Willett WC, et al. Roles of drinking pattern and type of alcohol consumed in coronary heart disease in men. N Eng J Med 2003;348(2):109–118.

2.  Tolstrup J, Jensen MK, Tjonneland A, Overvad K, Mukamal KJ, Gronbaek M. Prospective study of alcohol drinking patterns and coronary heart disease in women and men. BMJ 2006;332(7552):1244–1247.

3.  Hvidtfeldt UA, Gottlieb Hansen AB, Grønbæk M, et al.  Alkoholforbrug i Danmark – kvantificering og karakteristik af storforbrugere og afhængige. Statens Institut for Folkesundhed, Syddansk Universitet, 2008.

4.  Grønbæk M, Becker U, Johansen D, Gottschau A, Schnohr P, Hein HO, Jensen G, Sørensen TIA. Type of alcohol consumed and mortality from all causes, coronary heart disease, and cancer. Ann Intern Med 2000; 133: 411–419.

5.  Mukamal KJ, Maclure M, Muller JE, Mittleman MA.  Binge drinking and mortality after acute myocardial infarction.  Circulation 2005;112;3839-3845/

6.  Corrao G, Rubbiati L, Bagnardi V, Zambon A, Poikolainen K.  Alcohol and coronary heart disease: a meta-analysis.  Addiction 2000;95:1505–1523.

7.  Di Castelnuovo A, Costanzo S, Bagnardi V, Donati MD, Iacoviello L, de Gaetano G.  Alcohol dosing and  total mortality in men and women. An updated meta-analysis of 34 prospective studies.  Arch Intern Med 2006;166:2437-2445.

8.  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-analysis.  Eur J Epidemiol 2011;DOI 10.1007/s10654-011-9631-0

9.  United Kingdom, Department of Health. Sensible drinking. London: 1995.

Forum Summary

In a well-done, population-based analysis from Denmark, it was found that subjects who were overall “light-to-moderate” drinkers but reported an episode of “binge drinking” (consumption >5 drinks on an occasion) did not show differences in risk of ischemic heart disease (coronary disease) or total mortality than did other moderate drinkers who did not report such an episode.  These results are somewhat different from results of many other epidemiologic studies that have shown increased risk of health problems (even higher risk of coronary disease) to be associated with what was referred to as “binge drinking.”

Why there were no adverse effects of such drinking in the present study has provoked considerable discussion among members of the Forum.  The general consensus of opinion has to do with inconsistencies in the definition of “binge drinking.”  The rapid consumption of more than 5 drinks on an empty stomach surely has different effects than the consumption of alcohol over several hours with food, such as during a prolonged dinner.  The rate of consumption strongly affects the consequences of alcohol; in fact, some have suggested that the consumption of more than 2 or 3 drinks in less than two hours may constitute a better definition of binge that the total number of drinks. 

The Forum continues to suggest that “binge drinking,” however defined, is not a healthy pattern of alcohol consumption.  But the circumstances of consumption (rate of consumption, with or without food, etc.) may also be important in its definition and in judging its effects on health.

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

Erik Skovenborg, MD, Scandinavian Medical Alcohol Board, Practitioner, Aarhus, Denmark

Creina Stockley, clinical pharmacology, Health and Regulatory Information Manager, Australian Wine Research Institute, Glen Osmond, South Australia, Australia

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

Fulvio Ursini, MD, Dept. of Biological Chemistry, University of Padova, Padova, Italy

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

Giovanni de Gaetano, MD, PhD, Research Laboratories, Catholic University, Campobasso, Italy

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

Harvey Finkel, MD, Hematology/Oncology, Boston University Medical Center, Boston, MA, USA

Tedd Goldfinger, DO, FACC, Desert Cardiology of Tucson Heart Center, Dept. of Cardiology, University of Arizona School of Medicine, Tucson, Arizona, USA

Ulrich Keil, MD, PhD, Institute of Epidemiology and Social Medicine,  University of Münster, Münster, Germany

Francesco Orlandi, MD, Dept. of Gastroenterology, Università degli Studi di Ancona. Italy