Blog | Monday, July 14, 2014

QD: News Every Day--Another piece to the puzzle of alcohol and heart health

A single gene variation may lead to less alcohol consumption, and may be the reason why there is a perceived health benefit to moderate drinking, a meta-analysis concluded

A variant in the alcohol dehydrogenase 1B gene (ADH1B) leads people to break down alcohol faster, but also causes nausea and embarrassing symptoms such as facial flushing. This leads to drinking less, which is associated with less binging, lower blood pressure, a smaller waist size, and a lower body-mass index. These, in turn, may pass on the benefit of less cardiovascular disease.

The study appeared at BMJ.

Researchers did a meta-analysis of 56 epidemiological studies of nearly 262,000 people of European descent, including more than 20,000 coronary heart disease cases and 10,000 stroke events.

Compared to noncarriers, people with the ADH1B gene drank 17.2% fewer units of alcohol per week (95% CI, 15.6% to 18.9%), had a lower prevalence of binge drinking (odds ratio [OR], 0.78; 95% CI, 0.73 to 0.84), abstained more often (OR, 1.27; 95% CI, 1.21 to 1.34).

Compared to noncarriers, those with the gene had lower systolic blood pressure (−0.88 mm Hg; 95% CI, −1.19 to −0.56), lower interleukin-6 levels (−5.2%; 95% CI, −7.8 to −2.4%), a narrower waist circumference (−0.3 cm; 95% CI, −0.6 to −0.1), and a lower body mass index (−0.17 kg/m2; 95% CI, −0.24 to −0.10).

Carriers also had lower odds of coronary heart disease (OR, 0.90; 95% CI, 0.84 to 0.96). The protective association of the gene remained the same whether the people were light, moderate or heavy drinkers (P=0.83 for heterogeneity). Gene carriers had lower odds of ischemic stroke (OR, 0.83; 95% CI, 0.72 to 0.95), although there was no association across all types of stroke.

The findings suggest that reduction of alcohol consumption, even for light to moderate drinkers, is beneficial for cardiovascular health, researchers noted.

A co-author said in a press release, “For some time, observational studies have suggested that only heavy drinking was detrimental to cardiovascular health, and that light consumption may actually be beneficial. This has led some people to drink moderately based on the belief that it would lower their risk of heart disease. However, what we’re seeing with this new study, which uses an investigative approach similar to a randomized clinical trial, is that reduced consumption of alcohol, even for light-to-moderate drinkers, may lead to improved cardiovascular health.”

An editorial noted that drawing firm conclusions are still difficult, but that more researcher and diverse types of studies are still important to making an eventual conclusion about the role of alcohol and heart health. “Combining evidence from multiple research designs (that is, ‘design diversity’) will prove enlightening in the long run, even if conclusions are puzzlingly inconsistent and difficult to interpret in the short run.”