Alcohol and blood pressure

A new study published in PLoS Medicine shows that individuals who drink on a regular basis have a systolic blood pressure around 7 mmHg higher than that of people who do not drink.

The researchers, led by Sarah Lewis from the University of Bristol, UK investigated the results of five published studies which looked at the association between blood pressure and a variation in the gene for the enzyme that removes alcohol from the body, aldehyde dehydrogenase 2 (ALDH2). People who inherit two copies of the variant form of this gene from their parents have the ALDH2 *2*2 genotype and become flushed and nauseated after drinking. Consequently, they drink less than people with a *1*2 genotype and much less than those with a *1*1 genotype. Because inheritance of these genetic variants does not seem to affect lifestyle factors other than alcohol intake, an association between ALDH2 genotypes and blood pressure would indicate that alcohol intake has an effect on blood pressure.

The studies were mainly done in Japan where the ALDH2 gene variant is common. A combined (meta) analysis showed that men with the *1*1 genotype (and hence highest alcohol intake) and those with the *1*2 genotype (intermediate alcohol intake) were 2.42 and 1.72 times more likely, respectively, to have hypertension than those with the *2*2 genotype (lowest alcohol intake). There was no association between ALDH2 genotype and hypertension among the women in these studies because they drank very little.

These findings support the suggestion that alcohol has a marked effect on blood pressure, at least for Japanese men. Additional large-scale studies are needed to confirm the finding in more people, and to improve the estimates of the effect that alcohol intake has on blood pressure.

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