A recent study aimed to evaluate the relation among alcohol consumption, the metabolic syndrome, and the risk of ischemic heart disease (IHD, another name for coronary heart disease). The study was conducted in a cohort of 1,966 men from the Quebec Cardiovascular Study. All men were initially free of IHD and, during the follow-up period of 13 years, 219 first cases of IHD were diagnosed. Alcohol consumption was determined by calculating the g/d intake based on standard portions of beer, wine, and spirits. Metabolic syndrome was diagnosed according to a modification of the National Cholesterol Education Program Adult Treatment Panel III definition.
Men who consumed ≥15.2 g of alcohol/d (4th quartile of the distribution) were younger (P < 0.001), had elevated plasma HDLC concentrations (P < 0.001), and lower plasma concentrations of insulin (P = 0.01), CRP (P = 0.01), and fibrinogen (P < 0.001) than men in the 1st quartile (<1.3 g of alcohol/d). After adjustment for a series of coronary risk factors, alcohol consumption ≥ 15.2 g/d was associated with a 39% reduction in the 13-y risk of IHD [relative risk (RR) of IHD = 0.61, P = 0.02].
Finally, an alcohol consumption < 15.2 g/d was associated with an increase of the risk of IHD in men with the metabolic syndrome (RR = 2.24, P < 0.001) but not in men without the metabolic syndrome (RR = 1.31, P = 0.22). The authors state that these results confirm that moderate daily alcohol consumption has cardioprotective properties and suggest that the effects may be more important in subjects with a deteriorated risk profile, such as those with the metabolic syndrome.
Comments by R.Curtis Ellison: This relatively small observational study from Canada did not have data available on waist circumference or fasting blood glucose, two components of the metabolic syndrome (MS), but used substitute measurements: BMI for waist circumference and fasting insulin levels or reported diabetes for fasting blood glucose.
As expected, most cardiovascular risk factors showed an inverse association with alcohol consumption, with drinkers having higher levels of HDL cholesterol and lower levels of insulin, fibrinogen, and CRP. The exception was systolic blood pressure, which was lower than in the referent group (reporting < 1.3 g/day, or less than one drink per week) for consumers of 5.5-15.1 g/day, but higher with greater alcohol consumption. Both diabetes and the MS showed a linear decrease with increasing amounts of alcohol consumed.
In terms of the risk of IHD, men in the highest quartile of alcohol consumption (versus those in the lowest quintile) had about 40% lower risk of developing IHD during the 13 years of follow up. There was essentially the same effects when a very large number of risk factors (including HDL, diabetes, systolic blood pressure, and insulin, which are thought to be intermediary factors in the effects of alcohol) were adjusted for, suggesting that most of the protection against IHD of alcohol is not due to these factors.
In somewhat unusual manipulations, the authors also judged whether the metabolic syndrome increased the risk of IHD differently in men consuming < 15.2 g/day and those consuming ≥ 15.2 g of alcohol per day. In both groups, risk of IHD was higher with the MS. The effects of alcohol wereslightly more striking among subjects with the MS, but we do not agree with the authors’ interpretation that the reduction in IHD risk is “much greater among subjects with the MS.”
They are basing this conclusion on comparisons of groups where there were small numbers in some of the cells, and seem to be basing their conclusions primarily on statistical significance; the relative risks were not that different. Indeed, they report that “the statistical interaction between alcohol consumption and metabolic syndrome in modulating the risk of IHD was not significant.”
While the present study does not add greatly to our understanding of the relation of alcohol to the metabolic syndrome and heart disease, it provides additional support for the closing remarks of the authors that “there is now compelling evidence to support the concept that light-to moderatealcohol intake may be part of a healthy lifestyle.”
Article: Gigleux I et al. Moderate alcohol consumption is more cardioprotective in men with the metabolic syndrome. J Nutr 2006;136:30273032.