“Everything the hujur tells is very educative but if I can’t not apply those in my own life then there is no meaning”: A mixed-methods process evaluation of a smoke-free homes intervention in Bangladesh.

Background Exposure to second-hand smoke from tobacco is a major contributor to global morbidity and mortality. A cluster RCT in Bangladesh concluded a community-based smoke-free home (SFH) intervention delivered in mosques, with or without indoor air quality (IAQ) feedback to households was neither effective nor cost-effective compared to no intervention. This paper presents the process evaluation embedded within the trial. Methods A mixed method process evaluation comprising interviews with 30 household leads and six imams, brief questionnaire administered to 848 household leads, fidelity assessment of intervention delivery in six mosques and research team records. Data sets were triangulated using meta-themes informed by three process evaluation functions: implementation, mechanisms of impact and context. Results IMPLEMENTATION: The frequency of SFH intervention delivery was judged moderate to good. However there were mixed levels of intervention fidelity and poor reach. Ayahs-messages targeting SHS attitudes were most often fully implemented and had greatest reach (with social norms). Frequency and reach of IAQ feedback intervention were good. MECHANISMS OF IMPACT: Both interventions had good acceptability. However, views on usefulness of the interventions were mixed. Only half of households reported achieving a SFH home at 3-months follow-up. Individual drivers to behaviour change were new SFH knowledge with corresponding positive attitudes, social norms and intentions. Individual barriers were a lack of self-efficacy and plans. CONTEXT: Social context drivers to SFH intervention implementation in mosques were in place and important. No context barriers to implementation were reported. Social context drivers to SHS behaviour change were children’s requests. Barriers were a reluctance to request visitors to smoke outside. (Not) having somewhere to smoke outside was a physical context (barrier) and driver. Conclusions Despite detailed development and adaption work with relevant stakeholders, the SFH and IAQ interventions became educational interventions that were motivational but insufficient to overcome significant context barriers to SHS behaviour change. Embedding these interventions into community wide strategies that include practical cessation support and enforcement of SFH legislation is needed.