A systematic review and meta-analysis by Michael Roerecke and colleagues published in the February edition of The Lancet extends knowledge of the association between alcohol and blood pressure by showing a dose-dependent association between baseline alcohol intake and the blood pressure-lowering effect of a subsequent reduction in alcohol intake, with an apparent threshold at two standard drinks (24 g pure alcohol per day).
No significant effect of lowering alcohol consumption was recorded in individuals with a daily intake of two or fewer drinks and effect sizes were greatest in those who had the highest intake beyond two drinks per day, irrespective of baseline cardiovascular risk. For example, in people who drank six or more drinks per day, a reduction in alcohol intake of about 50% was associated with mean reductions in systolic and diastolic blood pressure of 5·50 mm Hg and 3·97 mm Hg, respectively, similar to the benefit of other lifestyle changes such as increased physical activity and weight loss. The authors state that it is likely that a sustained reduction in alcohol consumption in people drinking more than two drinks per day will be accompanied by a reduction in both blood pressure and subsequent cardiovascular events. Their findings indicate a protective benefit of low-moderate alcohol intake (ie, 1–2 drinks per day), whereas consumption of more than two drinks per day is associated with adverse outcomes.
The authors comment that it remains unclear whether one to two drinks per day have protective, neutral, or harmful effects, therefore contemporary guidelines for both hypertension and cardiovascular disease prevention recommend moderation of alcohol consumption, corresponding to approximate daily intakes of less than 20 g in men and less than 10 g in women. Although the results presented agree with the recommendations for men, data for women were scarce and should be interpreted cautiously. For this reason, it seems reasonable to continue with the current sex-specific recommendations until further evidence is available.
Source: Alcohol and blood pressure. Manan Pareek, Michael Hecht Olsen. The Lancet Volume 2, No. 2, e63–e64, February 2017. thelancet.com/journals/lanpub/article/PIIS2468-2667(17)30009-9/fulltext9.