mHealth smoking cessation intervention among high-school pupils (NEXit Junior): study protocol for a randomized controlled trial.

Background: Mobile health (mHealth) interventions, using text messages to support high-school pupils to quit smoking, could be a novel and cost-effective approach. However, more research is needed, specifically to investigate long-term effectiveness. The study aims to evaluate the effectiveness of a newly developed mHealth intervention targeting smoking cessation among high-school pupils.

Methods: The study is a two-arm, randomized controlled trial with an intervention group (mHealth intervention) and a control group (treatment as usual: national smoking cessation help line). Outcome measures will be investigated at baseline and at 3, 6, and 12 months' follow-up. Primary outcome measures will be: prolonged abstinence and 4-week point prevalence of smoking abstinence. Secondary outcome measures will be: 7-day point prevalence of smoking abstinence; mean number of quit attempts since taking part in the study; number of uses of other smoking cessation services since first invitation to the study and number of cigarettes smoked weekly if still smoking.

Conclusions: High schools in Sweden are bound by law to offer a smoke-free environment. However, little effort has been made to offer support to pupils who wish to quit smoking; rather the emphasis is on prevention of uptake. The study will examine the effectiveness of a stand-alone mHealth intervention targeting smokers among high-school pupils. Background: The trial was not retrospectively registered and has been registered at ISRCTN with the unique identification number ISRCTN15396225 . The trial was registered on 13 October 2017.