London: Influential students trained to propagate anti-smoking messages among friends and peer groups can discourage the habit in schools, according to a recent study.

Evidence suggests that although teenagers associate with like-minded people engaging in similar behaviour, peer influence can be protective and harnessed for positive effect through education.

The study involved 11,000 students aged 12 and 13 years in 59 schools across western England and Wales, to propagate new norms of non-smoking behaviour among them.

Of these, 29 schools (5,372 students) were randomly assigned to the control group, and continued their normal smoking education, and 30 schools (5,358 students) were assigned to receive a special training programme in addition to their normal education. Follow-up data were collected immediately after the intervention and after one and two years.

Saliva samples were analysed as well as self-reporting to establish whether the young person had been smoking.

First, young people were asked to nominate influential students in their year group, and the most popular nominees were invited to a recruitment meeting.

The role of being a peer supporter was explained to them, and their consent was requested to attend a training course, as well as their parents' consent.

They also received further training and support during four school-based sessions. Over a 10-week period following the training, the peer supporters were asked to have conversations with other students in their year group about the benefits of not smoking.

Researchers found that students in the intervention group of schools were 25 percent less likely to take up regular smoking than those in the control group immediately after the programme had been run in their school.

About 23 percent were less likely to start regular smoking after one year and 15 percent less likely after two years.

The corresponding percentage reductions for the high-risk group were 21 percent (immediately after), 25 percent (after one year) and 15 percent (after two years).