Alcohol and coronary heart disease1 | International Journal of Epidemiology | Oxford Academic
to ; P for trend ) after adjustment for age, aspirin use, smoking, physical activity, body mass consumption has a similar association with CHD among. BACKGROUND Understanding the relationship between alcohol abuse, a common and theoretically modifiable condition, and the risk factors for cardiovascular disease is of particular .. With the exception of male sex and smoking, the. The strongest association was with wine and this was independent of cigarette consumption, dietary intake and relation between CHD mortality and alcohol consumption.
This means that at a certain level of drinking, the protective effect disappears, and mortality rate starts to increase. This is equivalent to slightly less than two drinks daily Alcohol and High Blood Pressure High blood pressure hypertension is an important risk factor for heart disease and stroke.
Drinking more than two drinks a day is associated with an almost twofold risk of hypertension. In a meta-analysis of 15 randomized controlled trials on patients with hypertension, reducing alcohol intake was associated with lowering of blood pressure Similar results have been found for women with type 2 diabetes Another question is whether moderate alcohol consumption may lower the risk of developing diabetes.
A meta-analysis of observational studies suggests a 30 percent reduced risk of type 2 diabetes in moderate alcohol consumers Stroke is the 4th leading cause of death in the US.
Alcohol Consumption and Risk for Coronary Heart Disease in Men With Healthy Lifestyles
The association between alcohol consumption and stroke was assessed in a meta-analysis In fact, light alcohol consumption had no effect on the risk of stroke and consumption of more than two drinks daily was associated with an increased risk of ischemic stroke. The lowest risk for stroke was seen in men who drank one to two drinks daily three to four days a week. However, this effect was found only for red wine but not for other alcoholic beverages.
Does Beverage Type Matter? Other studies have reported that when it comes to heart disease, more health benefits may be expected from drinking wine compared with other alcoholic beverages 22 It has been highlighted that red wine contains polyphenols that have antioxidant properties. However, there is still no clear evidence that red wine is better than other forms of alcohol when it comes to improving heart-health.
Furthermore, there appear to be positive effects on blood coagulation, reducing the risk of thrombosis. Alcohol also increases adiponectin levels Adiponectin is associated with less risk of diabetes and coronary heart disease. Longitudinal studies The findings of case-control studies have been confirmed by seven longitudinal studies Table 3.
These were conducted on men and women, and in populations as culturally and ethnically different as Japanese-Americans, Yugoslavs, rural and urban Puerto-Ricans, white Americans and British civil servants. They used a variety of methods of assessing alcohol and a variety of analytical techniques. All were consistent with a higher CHD incidence in non-drinkers than in drinkers.
Alcohol and Heart Disease | Benefits and Harms of Alcohol
Only the Chicago study 11 showed a clear-cut intake six pints daily above which CHD incidence may have risen. It is likely that few problem drinkers were included in these studies.
Is the lower CHD risk in moderate drinkers due to factors other than alcohol? This could account for the higher mortality in non-drinkers, but it is unlikely to be the whole explanation. The data from the recent Swedish study, by themselves, are not convincing. Their speculation that the high mortality in abstainers occurs to ex-drinkers is based on a total of seven deaths in the abstainers, of which four had been diagnosed at the time the alcohol questionnaire was administered and two lung embolism and hepatitis may have been alcohol related.
Whether these men had been drinkers in the past is not known. Alcohol histories are notoriously inaccurate, although when they have been compared with biochemical measures of the effects of alcohol the correlation has been found to be high enough for some purposes.
Simple inaccuracies would blur true associations and therefore could not account for the observed results; neither could underreporting by heavy drinkers unless they declared themselves to be total abstainers.
Two of the studies, in Hawaii 21 and San Francisco, 19 found an inverse dose-response relationship higher alcohol-lower CHD. It seems unlikely that denial of drinking could per se account for this association. Most of the studies reviewed above controlled for major known coronary risk factors, particularly smoking, and the negative association between CHD and alcohol was independent of these.
It remains a possibility that non-drinkers may differ from moderate drinkers in other ways that put them at high risk, e. But differences in fat intake were small and inconsistent for men and women. This factor X would have to be more common in countries with lower than countries with higher alcohol consumption, and would have to have changed in frequency in the USA in the opposite way to alcohol consumption, increasing in the late s and s and declining again in the s and s.
There may indeed be a complex of factors that could explain away the above findings. A simpler explanation is that moderate drinking is protective.
How might alcohol protect against CHD? The findings on this point do not, at the moment, implicate one type of drink over another. St Leger et al. The other studies did not distinguish type of alcoholic drink.
Possible mechanisms Atheroma There is not general agreement, but there have been reports of less atheroma in alcoholics at autopsy. One study of patients undergoing coronary angiography 29 found significantly lower occlusive scores in moderate than in non-drinkers.
Such studies are difficult to interpret because of the biased selection of patients. Thrombosis Alcohol in large amounts can produce thrombocytopaenia and decreased platelet aggregation. Meade has reported that drinkers have lower fibrinogen levels and higher fibrinolytic activity than non-drinkers.
Is the negative association causal?
Alcohol and Heart Disease
There is some evidence of an increased risk of CHD in heavy drinkers. This is not a crucial public health question, however, as there is sufficient evidence of the hazards of heavy drinking to make it undesirable, regardless of a possible relation with CHD.
The evidence that moderate alcohol consumption may be protective may be assessed in relation to the formal criteria for a causal association. Strength The relative risk for moderated alcohol consumption is of the order of 0. Conversely observational studies also indicate that moderate drinkers have higher levels of homocysteine, a substance derived from breakdown of the amino acid methionine that may increase the risk of blood clots.
Only modest experimental data exist, however, to confirm either relationship Imhof et al. Small studies have found mixed results of the effect of alcohol consumption on the function of the endothelial lining of the blood vessels. Laboratory experiments have suggested that regular alcohol consumption might increase the endothelial cells' production of and responsiveness to nitric oxide, a small molecule made in blood vessel walls that helps to relax constricted blood vessels and thereby improve blood flow to organs such as the heart.
If these findings can be confirmed, they could suggest another mechanism through which alcohol consumption may prevent myocardial infarction. For example, because men and women differ in how they metabolize alcohol and in their underlying risk of cardiovascular disease, they may also differ in how alcohol consumption relates to their risk of heart disease. Such variability is difficult to assess in randomized trials of alcohol consumption, which have been too small to allow subgroup comparisons.
Observational studies, however, provide some intriguing answers to this question. For example, the studies of healthy men Rimm et al. These studies also demonstrate, however, that the level of alcohol consumption associated with the lowest risk of heart disease is lower among women than among men, consistent with public health recommendations that advise consumption of no more than two drinks per day for men and no more than one drink per day for nonpregnant women.
Genetic factors may also modify the relationship between moderate drinking and coronary heart disease in interesting ways. For example, the initial breakdown of the alcohol contained in alcoholic beverages-chemically referred to as ethanol-is mediated by an enzyme called alcohol dehydrogenase ADH. Of these, ADH3 has two common genetic variants, or alleles, that break down ethanol at different speeds i. Each person carries two copies of the ADH3 gene, one inherited from the father and one inherited from the mother.
Accordingly, a person can carry either two fast alleles, two slow alleles, or one fast and one slow allele of the ADH3 gene. A recent study of men with myocardial infarction and control men studied the relationship between these ADH3 alleles and the risk of heart disease Hines et al.
The study found that compared with men who carried two copies of the fast allele and drank less than once per week, men who carried two copies of the fast allele and drank daily had a 38 percent lower risk of myocardial infarction. In contrast, daily drinkers who had two copies of the slow allele had an 86 percent lower risk of myocardial infarction compared with men with two slow alleles who drank less than weekly.
These results suggest that, within the range of moderate drinking, greater exposure time to alcohol on the basis of more frequent drinking and slower metabolismmay lower one's risk of myocardial infarction. This finding provides a plausible explanation for the gene-related variation in the relationship between alcohol consumption and risk of myocardial infarction described in the study. Danish investigators reported intriguing findings in a study of 3, men Hein et al.
The investigators compared the risk of cardiovascular mortality among men with different Lewis blood group types. People with the AB blood type seem to be at higher risk for diabetes and cardiovascular mortality than people with other Lewis blood types. Among men with other Lewis blood group types, however, alcohol consumption was not appreciably related to the risk of heart disease.
Taken together, these two studies suggest that genetic factors that influence potentially beneficial variables linked to alcohol use e. Based on the results of the meta-analysis of randomized trials by Rimm and colleaguesthe answer appears to be yes.
If alcohol consumption indeed influences HDL-C, triglyceride, and fibrinogen levels to the degree documented in the meta-analysis, consumption of two standard drinks daily would be expected to lower a person's risk of coronary heart disease by nearly 25 percent, a figure that agrees well with the results of observational studies. Obviously, however, alcohol consumption also has serious and important health effects other than those related to coronary heart disease, which are reviewed elsewhere in this journal issue.
Achieving a balance between the health risks and benefits of alcohol consumption remains difficult, as each person has a different susceptibility to the adverse health consequences associated with alcohol consumption. Because each person has a unique combination of factors-such as age, sex, and family history-that influence that person's risk of specific diseases potentially caused or prevented by alcohol use, the balance of the risks and benefits of alcohol consumption for each person likewise will be unique.
Accordingly, a young woman with a family history of alcoholism should weigh the decision of how much alcohol to drink if any differently than should a middle-aged man with a family history of premature heart disease. One approach to examining the combined results of potentially detrimental and beneficial effects associated with alcohol consumption is to assess the overall rates of death in people who consume different amounts of alcohol.
Such studies of all-cause mortality can combine the baseline risk of dying from each specific disease with the increase or decrease in the risk for that disease associated with alcohol consumption. Obviously, observational studies of all-cause mortality are susceptible to the same concerns discussed earlier regarding studies of coronary heart disease. Nevertheless, the apparent agreement of clinical and observational studies regarding the relationship between alcohol consumption and coronary heart disease provides reassurance about the validity of these reports.
Given that over 30 percent of deaths in the United States are attributable to heart disease, making it the nation's leading cause of death, it is not surprising that observational studies show that moderate drinkers have lower overall death rates than do abstainers or heavy drinkers. For example, in an American Cancer Society study ofadults, death rates among middle-aged and elderly men and women were lowest among people who consumed approximately one drink per day Thun et al.
In fact, death rates among these moderate drinkers were approximately 20 percent lower than among abstainers. The level of alcohol consumption associated with the lowest overall death rate, however, differed substantially based on the participants' age and risk of heart disease. In light of the substantial and often contradictory evidence regarding the health effects of alcohol consumption, one cannot make a simple recommendation regarding the "optimal" level of alcohol consumption.
In the absence of such a straightforward recommendation, people should consult their physicians regarding the safety or risk of alcohol consumption and make personalized decisions accordingly.
Alcohol consumption and mortality. Characteristics of drinking groups. Alcohol consumption and mortality among women. New England Journal of Medicine Alcohol consumption, Lewis phenotypes, and risk of ischaemic heart disease. Genetic variation in alcohol dehydrogenase and the beneficial effect of moderate alcohol consumption on myocardial infarction.
Effect of alcohol consumption on systemic markers of inflammation.
Determinants of plasma total homocysteine concentration in the Framingham Offspring cohort. American Journal of Clinical Nutrition Alcohol, blood pressure, and hypertension. Novartis Foundation Symposium Demonstration of deductive meta-analysis: Haemostatic function and ischaemic heart disease: Principal results of the Northwick Park Heart Study.
Journal of Studies on Alcohol Prospective study of C-reactive protein and the risk of future cardiovascular events among apparently healthy women. Prospective study of alcohol consumption and risk of coronary disease in men. Review of moderate alcohol consumption and reduced risk of coronary heart disease: Is the effect due to beer, wine, or spirits? British Medical Journal Moderate alcohol intake and lower risk of coronary heart disease: Effect of ethanol on platelet function.
Clinical and Experimental Research Alcohol and mortality in British men: Explaining the U-shaped curve. A prospective study of moderate alcohol consumption and the risk of coronary disease and stroke in women. A prospective study of cholesterol, apolipoproteins, and the risk of myocardial infarction.