Many South African adolescents lead unhealthy lives overshadowed by violence, are at grave risk of HIV infection and have considered suicide, according to the bleak findings of the first national survey of risk-related youth behaviour.

The survey of 10,699 adolescents, one of a handful of such studies worldwide, was commissioned by the health department and carried out with the education department in late 2002.

In a land where one in 10 people is living with HIV-Aids, 41 per cent of the secondary pupils surveyed had had sex (about half of boys and a third of girls), 14 per cent of them before the age of 14. Nearly one in 10 had been forced to have sex at some stage.

Among the 15 to 18-year-olds who had had sex, 54 per cent had had more than one partner, seven in 10 had had sex in the previous three months and 16 per cent had been pregnant.

But it is not all bad news: 29 per cent of sexually active teenagers consistently use condoms - compared with 4 per cent of adolescents in a 1994 study in Western Cape - and 72 per cent have received HIV-Aids education.

Half of South Africa’s nearly 45 million people are below the age of 19, and 12m are at school. All are experiencing the multifaceted transitions of a country moving from authoritarian to democratic rule, and most are poor.

The Youth Risk Behaviour survey was conducted in state schools. Pupils aged 14 to 19 years were weighed, measured and asked questions in five priority categories: intentional and unintentional injuries; substance abuse; sexual behaviour; nutrition; and physical activity and hygiene.

It was found that during the previous month nearly one in 10 pupils had carried a weapon such as a gun or knife on school property; nearly 15 per cent had been threatened or injured with a weapon; 19 per cent had been hurt in fights; and more than 40 per cent had been bullied.

Not surprisingly, a third felt unsafe at school. More than 13 per cent said they had assaulted their boyfriend or girlfriend. Safety and crime are “enormous challenges facing schools”, said education minister Kadar Asmal.

One shocking finding was that, during the previous six months, a quarter of adolescents had felt sad or hopeless, one in five had considered suicide and 17 per cent had attempted suicide. Of those who attempted suicide, 28 per cent required treatment.

An analysis of nutritional status revealed stunting due to malnourishment in 11 per cent of pupils, while nearly one in 10 was underweight. As worrying was the fact that 17 per cent were overweight and 4 per cent were obese.