A child under 10 undergoes hospital treatment for alcohol-related problems once every three days in England, according to government figures released on Sunday. And the number of under-age drinkers being treated overall jumped 40% in just one year, from 2006 to 2007. To qualify as an alochol-related admission, the diagnosis must mention either mental and behavioural disorders due to alcohol use, alcoholic liver disease, or the toxic effect of alcohol.

Meanwhile, a report published earlier this month on the number of pupils excluded from school for drinking made for equally alarming reading. It revealed that in the past four years, 2,000 pupils have been permanently excluded and a further 40,000 temporarily excluded for alcohol and drug-related incidents.

Educational problems aside, there is good evidence to show that the use of alcohol by under-18s is linked to a litany of high-risk behaviours, including unsafe (or unwanted) sex, traffic and other accidents, illegal drug use, family breakdown and even a higher risk of suicide.

But as if the behavioural problems caused by underage drinking aren't grave enough, researchers' attention has now turned to a more neglected area - the potential long-term health risks. Adolescence is a period of rapid growth, and a critical time for physical and emotional change. And although research in this area is in its early stages, it does suggest that underage drinking may cause physiological damage, even within a short time frame.

According to the National Institute on Alcohol Abuse and Alcoholism in the US, which has published a summary of the research so far, the chief areas affected by alcohol use seem to be the adolescent brain, bones, liver and the complex system of hormone production that is vital to normal growth and sexual development.

While it is still rare for young drinkers to encounter the type of chronic health problems adults get after cumulative years of drinking, research has also found that young people who start to drink early (14 years or under) may be at high risk of alcohol dependence in later life, with all the dangers to their health that this can entail. These include a risk of heart and liver disease, certain cancers, digestive disorders and even dementia.

So far, most of the research on the impact of alcohol on adolescent health has been carried out on either animals, or on young people who are officially classed as alcohol-dependent - and will therefore be drinking heavily on a regular basis. Without more studies, it's hard to say how far research on adolescent rats applies to young humans; and it's also difficult to know, at present, how much alcohol is too much and in what timeframe - whether, say, a once-a-week binge over months or years is sufficient to cause damage.

What we do know is that while the government sets limits on the amounts of alcohol it is safe for adults to consume, these obviously don't apply to those who are smaller, lighter and less developed physically. You might be surprised to learn, however, that young people have a higher tolerance to alcohol than adults. This means they're able to consume far more alcohol than adults can, before getting any unwanted effects - which may partly explain the high rates of binge drinking among young people. Unfortunately, research also suggests that binge drinking (consuming several units of alcohol in a short space of time) is more physically harmful than a regular but moderate intake.

Body of evidence

• By the age of 13, the proportion of those who drink exceeds the proportion of teenagers who do not.

• The UK has some of the highest levels of drunkenness among young people in Europe. Young boys drink mainly beer, cider and lager. Alcopops remain popular among girls but consumption of them tends to drop with age.

• Four per cent of 15-to-16-year-olds have been in trouble with the police through drinking.

• According to Frank Soodeen, former Alcohol Concern press officer: "There are more than 800,000 children below the age of 15 drinking regularly in the UK."

Carlene Thomas-Bailey

• Source: Alcohol Concern www.alcoholconcern.org.uk