A mixed-methods systematic review and synthesis of secondary care interventions to reduce secondhand smoke exposure among children and young people

INTRODUCTION: Childhood secondhand smoke exposure (SHSe) is linked with increased morbidity and mortality. Hospital or secondary care contact presents a 'teachable moment' to support parents to change their home smoking behaviours to reduce children's SHSe. This mixed-methods review explores: (1) if existing interventions in this context are effective, (2) if they are reported in sufficient detail to be replicated, (3) the experiences of HCPs delivering such interventions, and (4) the experiences of parents receiving such interventions.

METHODS: Five electronic databases and the grey literature were searched for relevant literature published and indexed January 1980 to February 2020. Fourteen papers reporting twelve studies (nine quantitative and five qualitative) were included. Aligned with the Joanna Briggs Institute method, a segregated approach was used involving independent syntheses of the quantitative and qualitative data followed by an overall mixed-methods synthesis.

RESULTS: There was some evidence of effective interventions that resulted in a short-term (< 6 months) reduction in children's SHSe when SHSe was subjectively measured. This was not seen in longer term follow-up (> 6 months) or when SHSe was measured objectively. Inconsistencies with reporting make replication challenging.Experiential evidence suggests a mismatch between stakeholder preferences and interventions being offered.

CONCLUSIONS: The paediatric secondary care interventions included in this analysis failed to show statistically significant evidence of longer-term effectiveness to reduce children's SHSe in all but one low quality study. There was also inadequate reporting of interventions limiting assessment of effectiveness. It offer further insights into areas to target to develop effective interventions.

IMPLICATIONS: This review used rigorous methods to explore the current, global literature on how children's exposure to SHS is being tackled in secondary care. This review identified only one low quality intervention study showing a statistically significant reduction in children's SHSe beyond six months. Synthesis with qualitative research identifies a mismatch between what parents want in an intervention and what has been delivered to date. Reporting quality needs to be improved to ensure that interventions can be replicated and studies conducted within the NHS to ensure suitability to this setting.