Children who smoke even a single cigarette at an early age are twice as likely to take up the habit later in life, even if they spend several subsequent years not smoking, a study has found.

Scientists argue that this "sleeper effect," which can be triggered by periods of stress or depression, means it is important to prevent teenagers from trying cigarettes even once.

Jennifer Fidler, of the Cancer Research UK Health Behaviour Unit at University College London, followed the smoking habits of more than 2,000 children for five years from the age of 11 at 36 schools in south London.

She said that teenagers who had tried smoking just once in previous years should be considered as new targets for anti-smoking messages.

This is the first study that shows that a very brief experimentation with cigarettes is predictive of later smoking despite a period of non-smoking in between is a dormant vulnerability.

"We were able to show that those students who had reported smoking just once were at an increased risk of taking up smoking by the age of 14, even if they had reported no smoking behavior in the intervening years," she said.

Of the 260 children who at age 11 said they had tried smoking just once, 18 per cent were smokers at age 14. By comparison, only 7 per cent of children who at age 11 said they had never smoked had started smoking by age 14.

Fidler's team found that the sleeper effect was still present after the usual factors that influence whether someone takes up smoking ethnicity, gender, social deprivation, and whether a person's parents smoke were taken into account. The results were published recently in the journal Tobacco Control.

Source: China Daily