Validity of self-reported indicators to assess secondhand smoke exposure in the home

Highlights: • Self-reported indicators showed moderate-strong correlations, low sensitivity and high specificity. • Low sensitivities suggest that SHS exposure could be underreported due to other SHS sources. • The self-reported exposure indicators studied are good to assess SHS exposure at home. • Questions about outdoor sources and third hand smoke should be included in questionnaires. Questionnaires are widely used to assess secondhand smoke (SHS) exposure. However, the validity of self-reported SHS exposure indicators has been rarely assessed. We aimed to assess correlations, sensitivity, specificity, and predictive values between self-reported SHS exposure indicators and airborne nicotine concentrations.