Just over one per cent of 11-year-olds admit to using drugs to boost their athletic performance, a new study from France shows.

Furthermore, four years later, three per cent said they had used doping agents at least once during the previous month.

"This result shows that doping does exist among very young athletes, whatever their level of sports participation, including leisure," Drs Patrick Laure and C. Binsinger of the Direction regionale de la Jeunesse et des Sports de Lorraine in Saint-Max conclude in the June issue of the British Journal of Sports Medicine.

Dr Laure and his colleagues had previously demonstrated that as many as 4 per cent of teens in southern France had used doping agents.

To understand the progression in use of these drugs over time, Dr Laure and Dr Binsinger followed 3594 student athletes from sixth to ninth grade.

In the first phase of the study, in the autumn of the students' sixth-grade year, 1.2 per cent said they had taken a doping agent at least once in the previous month.

The most common substance used was the asthma medication salbutamol, followed by corticosteroids, cannabis and stimulants and anabolic drugs.

Twenty-three per cent of the students who reported using doping agents said they used them daily, and 15 per cent said they used them at least once a week.

By the end of the ninth grade, when the researchers were able to interview 2199 of the original group, 3 per cent reported using doping agents. Twenty-four per cent said they used them daily, while 38 per cent said they used the drugs at least once a week.

Forty-four per cent of the study participants who admitted to using doping agents said the drugs had helped them win at least one competition.

Students who used doping agents reported lower self-esteem, scored higher on tests of anxiety, and were less likely to report feeling happy.

The findings suggest that adults who are in charge of young people should be aware of signs that they might be at risk of using performance-enhancing drugs, Drs Laure and Binsinger write.

"From a prevention point of view, this population of dedicated preadolescent athletes should be monitored," they conclude. "This will probably not be easy, as most users think that they won at least one competition as a result of their use of a prohibited substance".