New research suggests that the heart-health benefits long attributed to a glass of wine with dinner may be due to other lifestyle factors, not alcohol.

An international study published in the British Medical Journal found that even light to moderate alcohol intake was associated with a slightly increased risk for coronary heart disease and high blood pressure.

Michael Holmes, assistant professor at the Perelman School of Medicine at the University of Pennsylvania and co-lead author of the study, said the past studies linking light drinking with heart health have been observational, and this type of research has its limitations.

"We don't know whether or not the underlying mechanism was that alcohol reduced the risk of coronary heart disease or whether it was a marker for something else, i.e. these individuals also had a more favorable diet or they were more physically active," Holmes said.

To get better data, Holmes and his team of international researchers relied on a proxy for a randomized trial.

They analyzed data from more than a quarter of a million people and zeroed in on those with a gene that causes them to get flushed and nauseous after drinking.

Those with the gene tended to drink less -- on average a pint of beer a week -- and had about a 10 percent reduced risk of coronary heart disease and lower blood pressure.

"We found this across the spectrum of alcohol intake, so no matter how much alcohol you drink, if you're concerned about your risk of heart disease, you should reduce your intake," Holmes said.

Teetotalers with and without the gene did not exhibit the same cardiovascular health disparity. Cardiologists not affiliated with the study say that suggests the alcohol, not the gene, is causing the difference.

Still, health guidelines on moderate drinking are not likely to change due to one new study, cardiologists say.

"This suggests that there might not be the benefit that has been seen in observational studies, but I think that most clinicians aren't telling people who don't drink to go out and start drinking to protect their heart," said University of Michigan cardiologist Elizabeth Jackson. "It certainly doesn't put light to moderate drinking in the same category as smoking a pack of cigarettes."