Assessment of exposure to secondhand tobacco smoke in Spain: A scoping review

Introduction: There is no consensus on the questions that should be included in questionnaires to properly ascertain exposure to secondhand tobacco smoke (SHS). The objective of this study is to analyze the questions included in studies which have assessed SHS exposure in Spain. Methods: A scoping review was performed, using PubMed, Embase and Web of Science databases, selecting original articles published in English and Spanish, across the period 2012-2021. We extracted data from each study regarding its design, target population, sample size or geographical scope; we also collected data regarding how studies dealt with exposure to SHS including assessment and intensity of SHS, exposure setting, geographical scope, and the verbatim questions used. Results: Finally, 75 studies were identified. In the 23 studies carried out in children, verbatim questions were included in 8 studies, and the setting most studied was the home. SHS exposure was assessed during pregnancy and postnatally by 8 studies, the verbatim questions used were described in 2 studies, being exposure ascertained at home and workplace. In the adult population, 14 of 44 studies described the verbatim questions; the setting most studied was the home. Verbatim questions varied among studies. Conclusions: Questionnaire-based assessment of SHS exposure is highly heterogeneous, hindering comparability between studies. Therefore, it is necessary to set a standard questionnaire to assess exposure to SHS.