Background:
A few evidence-based interventions exist that have demonstrated effectiveness in promoting smoke-free homes yet have not been widely adopted and implemented. The purpose of this study was to adapt the “Some things are better outside” smoke-free homes intervention in Catalonia.

Methods:
We used a modified approach to Intervention Mapping (IM-Adapt) to guide adaptation. We used mixed methods approaches to better understand the factors that might influence smoke-free home policies in Catalonia. We convened an expert group comprised of researchers, representatives of local public health organisations, communitary health and participative research experts. The group performed an initial review of the intervention materials, mapping the intervention components and comparing them to local needs. In-depth interviews were conducted with intervention implementers and potential program participants. Further, focus groups were conducted to review and discuss the materials with the potential users. The expert group discussed preferences for various materials including the design elements, language, and look, and reached a consenus about the modifications to be made.

Results:
Overall, key stakeholders and potential users of the intervention reported a good fit of the intervention in terms of messaging and images although there were some specific recommendations to better respond the local cultural characteristics (e.g., photos of local people, housing characteristics, etc.). The most common adaptations included tailoring, refining, changing packaging, adding, and substituting. The major goals of the modifications were addressing cultural factors, increasing reach, improving the fit with users, and reducing cost. Stakeholders had many suggestions about implementation through schools in Catalonia and believed it would be an effective way to reach parents allowing smoking in homes.

Conclusions:
A systematic mixed methods approach involving key stakeholders of the intervention implementation was important for adapting a smoke-free home intervention to the Catalan context. We recommend the use of this participative approach to guide intervention adaptations.