BioEd Online

For young people, drinking even a small amount of alcohol could increase the chances of developing heart disease, according to one of the largest studies to look at alcohol's effects before middle age.

The finding contrasts with the widely held view that drinking in moderation - around two drinks per day for men and one for women - can help protect against heart disease.

Researchers are confident that this holds true for people who are over about 55 and at risk of heart disease. But they are unclear whether the health benefits of alcohol begin to accrue early in life - or exactly what alcohol is doing in the body to produce its beneficial effects.

Using data from an ongoing study on heart disease, epidemiologist Mark Pletcher at the University of California, San Francisco, and his team probed the hearts of more than 3,000 people aged 33-45 years using a CAT scanner.

They searched for one of the earliest signs of heart disease - a hardening of the arteries that supply oxygen to the heart itself. They then matched this up with information collected between 1985 and 2001 on how much each person drank.

The more a person imbibed, the greater their likelihood of showing artery hardening, the researchers found. Those who had more than 14 drinks per week, for example, were twice as likely to have artery problems than those who drank six or less.

This result is at odds with a commonly found pattern in other studies on alcohol and heart disease, in which those who drink moderately have a lower risk of problems than both teetotallers and those who drink heavily. "It was a surprise," Pletcher says, who reported the results in American Journal of Epidemiology¹.

Young at heart

The finding implies that drinking alcohol early in life does not rack up gradual benefits that will protect drinkers later on. "It suggests there is little to be gained at a young age," says Kenneth Mukamal, who studies alcohol and health at Harvard Medical School in Boston.

Instead, it backs the idea that a slug of liquor protects against heart disease in older people in a different way: by having almost immediate effects. It may, for example, cut the risk of a blood clot forming and choking off an artery.

The new study also confirms experts' view that binge drinking, defined as more than five drinks at one time, is harmful. Indeed, the researchers found it difficult to tell whether younger people who drank more were harming their arteries because of the total quantity they drank or because they tended to drink in binges. Both probably contribute, Pletcher says.

Ripe old age

The study is one of the first and largest to look in detail at the effects of alcohol on a young age group, in which the signs of impending cardiovascular problems are difficult to pick up. Most research has concentrated on older groups in which scientists can track more easily how many are struck by disease.

Public-health experts already believe that young drinkers gain little by drinking at a young age. Any positive effects on the heart are thought to be outweighed by the increased risk of cancer, accidents and injuries. "It might not be a good thing to recommend any alcohol," says Luc Djousse who studies preventative medicine at Boston University, Massachusetts.

Mukamal says that it will be difficult to pin down at what age the benefits of alcohol start to outweigh the risks. It could be done by examining those who take up drinking later in life, but very few people do this.

Meanwhile, public-health experts recognize that young people are unlikely to give up drinking because of seemingly remote risks of disease. So they say that standard advice still holds: if you are going to drink, do so in moderation.