People who drink regularly have higher systolic blood pressure than people who do not, according to a recent article published in PLoS Medicine. Researcher Sarah Lewis (University of Bristol, UK) and colleagues report that systolic blood pressure levels are about 7 mmHg higher in frequent drinkers than in people who do not drink.

Systolic blood pressure refers to the peak pressure in the arteries around the time that the heart muscle contracts. It is measured in millimeters of mercury (mmHg), and a normal value for a resting, healthy adult human is 120 mmHg.

The study authors conducted a meta-analysis by assessing results from five published studies. Each study focused on the link between blood pressure and a variation in the gene for aldehyde dehydrogenase 2 (ALDH2) - the enzyme that removes alcohol from the body.

Some individuals receive two copies of the variant form of this gene from their parents. They have the ALDH2 *2*2 genotype and experience adverse symptoms when drinking alcohol such as nausea and flushness. Other people receive a *1*2 genotype or a *1*1 genotype and consequently drink more alcohol than those with the *2*2 genotype. Since alcohol consumption seems to be the only lifestyle factor that the genetic variants affect, the authors argue that a relationship between ALDH2 genotypes and blood pressure is sufficient to establish a relationship between blood pressure and alcohol intake.

The ALDH2 gene variant is common in Japan, and most of the studies in the analysis were performed there. To aid interpretation of the results, the three genotypes can be grouped according to degree of alcohol intake:
  • *1*1 genotype has highest alcohol intake
  • *1*2 genotype has intermediate alcohol intake
  • *2*2 genotype has lowest alcohol intake
Those with the *1*1 variant were 2.42 more likely to have hypertension than those with the *2*2 variant. People with the *1*2 variant were 1.72 times more likely to have hypertension than those with the *2*2 genotype. The researchers found no link between ALDH2 and hypertension among the women subgroup because they drank very little on average.

Narrowly, the findings suggest that for Japanese men, the degree of alcohol consumption has an effect on blood pressure. In order to expand results and improve the estimate of alcohol's effect on blood pressure, additional large-scale studies are necessary.

Alcohol and blood pressure: A systematic review implementing a mendelian randomization approach.
Chen L, Davey Smith G, Harbord R, and Lewis SJ
PLoS Medicine (2008). 5(3): e52.
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About PLoS Medicine

PLoS Medicine is an open access, freely available international medical journal. It publishes original research that enhances our understanding of human health and disease, together with commentary and analysis of important global health issues. For more information, visit http://www.plosmedicine.org

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org

Written by: Peter M Crosta