March 4, 2008

Alcohol Consumption Increases High Blood Pressure Risk

British researchers report that people who regularly consume alcohol, even in moderate amounts, have higher blood pressure than those who do not drink. 

The study further revealed that those with a genetic mutation that makes it difficult to consume alcohol had substantially lower blood pressure than regular or heavy drinkers.

The scientists, led by Sarah Lewis at the University of Bristol, UK, examined the results of five published studies on 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 primarily performed 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 intake has a marked effect on blood pressure, at least for Japanese men.

The researchers said that people without the mutation who consumed 3 drinks a day had "strikingly" higher blood pressure than those with the genetic change who drank only small amounts or nothing at all.

And compared to those with the genetic mutation that made them drink less, the study found the risk of high blood pressure more than doubled among drinkers, and even increased 70 percent in those who were "quite modest" drinkers.

"This study shows that alcohol intake may increase blood pressure to a much greater extent, even among moderate drinkers, than previously thought," wrote Lewis and her colleagues in a report.   

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.


The study was published in the journal Public Library of Science Medicine. 

The full report can be viewed at http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0050052