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Diffusion of effects of the ASSIST school-based smoking prevention intervention to non-participating family members: a secondary analysis of a randomised controlled trial

Research output: Contribution to journalArticle

Original languageEnglish
Early online date26 Oct 2019
DateAccepted/In press - 14 Oct 2019
DateE-pub ahead of print (current) - 26 Oct 2019


To investigate whether effects of the ASSIST (A Stop Smoking In Schools Trial) school‐based smoking prevention intervention diffused from students to the people they lived with.

Secondary analysis of a cluster randomized control trial (cRCT).

England and Wales.

10,730 students aged 12‐13 years in 59 schools assigned using stratified block randomisation to the control (29 schools, 5,372 students) or intervention (30 schools, 5,358 students) condition.

Intervention and comparator
The ASSIST intervention involves 2‐days of off‐site training of influential students to encourage their peers not to smoke over a 10‐week period. The control group continued with their usual education.

The outcomes were the proportion of students who self‐reported living with a smoker and the smoking status of each resident family member/caregiver. Follow‐up assessments were immediately after the intervention and at 1 and 2 years post‐intervention.

The odds ratio for living with a smoker in the intervention compared with control group was 0.86 (95% confidence interval 0.72, 1.03) immediately after the intervention, 0.84 (0.72, 0.97) at a 1‐year follow‐up, and 0.86 (0.75, 0.99) at a 2‐year follow‐up. In a three‐tier multilevel model with data from all three follow‐ups, student‐reported smoking by fathers (OR = 0.90, 95% CI 0.80, 1.00), brothers (OR = 0.78, 95% CI 0.67, 0.92), and sisters (OR = 0.80, 95% CI 0.69, 0.92) was lower in the intervention compared with control group. Sub‐group analyses by baseline smoking status suggested these effects were more consistent with prevention of uptake than prompting cessation.

The ASSIST (A Stop Smoking In Schools Trial) school‐based smoking prevention intervention may have reduced the prevalence of smoking in people who lived with ASSIST‐trained students. This indirect transmission is consistent with the predictions of diffusion of innovations theory which underpins the design of ASSIST.

    Structured keywords

  • DECIPHer

    Research areas

  • smoking, prevention, peers, family, spill over, diffusion



  • Full-text PDF (author’s accepted manuscript)

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  • Supplementary information PDF

    Accepted author manuscript, 228 KB, PDF document

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