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The X:IT Study

Although the prevalence of adolescent smoking is decreasing up to 20% of adolescents whose parents receive welfare benefits, are smokers and adolescents from low SEP seem less likely to quit smoking in adulthood. When reaching vocational school, more than half are smoking. Most children and adolescents do not intentionally start smoking. Therefore, it is important early actively to prevent onset of smoking.

X:IT is a school-based intervention which has the potential to prevent up to 25% new smokers. However, the first evaluation showed that the intervention did not reach adolescents from high and low socioeconomic groups equally well. Therefore, X:IT has been revised and targeted this group of adolescents and their parents.


To conduct a scientific evaluation of the revised X:IT intervention. The overall aim is to decrease smoking by 25% among adolescents and to test whether the intervention is equally effective among high and low social classes. The intervention is targeted students in grade 7, 8, and 9.
The intervention
X:IT included three main intervention components:

  • smoke-free school grounds,
  • parental involvement comprising two dimensions – (a) smoke-free contract between the student and an adult person, preferably a parent, (b) smoke-free dialogues a smoke-free curriculum based on self-efficacy training and outcome expectancies.


The intervention includes around 50 schools all implementing X:IT. We examine adolescent smoking and factors related to smoking. Furthermore, we examine implementation of the intervention both at student and school level. All analyses will be stratified by socioeconomic status.

Measuring effect and evaluation
The effect of X:IT will be based on before- and after measures of adolescent smoking. The intervention will be followed to obtain thorough knowledge on implementation. This insight will be useful for future evaluation of the intervention.

Project period

The project runs for five years with the following main milestones:
2017: Recruitment of schools and municipalities, baseline data collection, and start of intervention
2018: The intervention is ongoing and follow-up data is collected after first year of intervention
2019: The effect after first year is presented. Data is collected after second year of intervention
2020: Data is collected after third year of intervention
2021: Results of the project is published.

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Go visit the project website

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Last Updated 19.10.2023