Assessment of exposure to second-hand tobacco smoke (SHS) using questionnaires in Portugal and Brazil: A qualitative study

This study aimed to identify the key concepts involved in designing epidemiological surveys to estimate the prevalence of second-hand tobacco smoke (SHS) exposure in Portugal and Brazil. A two-round Delphi study was conducted. Firstly, a group of experts was asked for their opinions on the relevance of various concepts (exposure scenarios, recall, time, environmental context, exposure intensity, and relationship to smoking) and domains. Based on their responses, a new questionnaire was developed. The experts ranked the importance of different questions. A thematic analysis was carried out. The experts considered it important to evaluate SHS exposure in general, as well as in specific settings, such as the home, workplace, public and private transport (with or without children), and leisure settings. They reported that recalling the number of hours of exposure spent indoors and outdoors on working and non-working days, and in the last month, provided a more detailed assessment. They also stated that exposure intensity should be assessed either by the presence and number of smokers or by the perception of a smoke-heavy environment. Differences in responses according to the country in which experts reside were minimal. The researchers provided clear, precise, and consistent recommendations for collecting comparable data across studies to enact smoke-free policies. This reinforces the feasibility of using standardised questionnaires to evaluate SHS exposure across countries.