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Socioeconomic inequalities in secondhand smoke exposure before, during and after implementation of Quebec’s 2015 ‘An Act to Bolster Tobacco Control’
  1. Thierry Gagné1,
  2. Josée Lapalme2,3,
  3. Adrian E Ghenadenik2,3,
  4. Jennifer L OLoughlin3,4,
  5. Katherine Frohlich2,3
  1. 1Epidemiology and Public Health, University College London, London, UK
  2. 2Centre de recherche en santé publique, Montreal, Quebec, Canada
  3. 3École de santé publique de l’Université de Montréal, Montreal, Quebec, Canada
  4. 4Centre de recherche du Centre Hospitalier de l’Université de Montré, Montreal, Quebec, Canada
  1. Correspondence to Dr Thierry Gagné, Epidemiology and Public Health, University College London, London WC1E 7HB, UK; t.gagne{at}


Background To better understand whether tobacco control policies are associated with changes in secondhand smoke (SHS) exposure across socioeconomic groups, we monitored differences in socioeconomic inequalities in SHS exposure in households and private vehicles among youth and adults before, during and after adoption of Quebec’s 2015 An Act to Bolster Tobacco Control.

Methods Using data from the Canadian Community Health Survey, we examined the prevalence of daily exposure to SHS in households and private vehicles among youth (ages 12 to 17) and adults (ages 18+) across levels of household education and income (separately) in 2013/2014, 2015/2016 and 2017/2018. We tested differences in the magnitude of differences in outcomes over time across education and income categories using logistic models with interaction terms, controlling for age and sex.

Results We detected inequalities in SHS exposure outcomes at each time point, most markedly at home among youth (OR of SHS exposure among youth living in the 20% poorest households vs the 20% richest=4.9, 95% CI 2.7 to 6.2). There were decreases in SHS exposure in homes and cars in each education/income group over time. The magnitude of inequalities in SHS exposure in homes and cars, however, did not change during this period.

Conclusions The persistence of socioeconomic inequalities in SHS exposure despite implementation of new tobacco control laws represents an increasingly worrisome public health challenge, particularly among youth. Policymakers should prioritise the reduction of socioeconomic inequalities in SHS exposure and consider the specific needs of socioeconomically disadvantaged populations in the design of future legislation.

  • surveillance and monitoring
  • socioeconomic status
  • secondhand smoke
  • prevention

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  • Twitter @thierrygagn, @josee_lapalme

  • Contributors TG, JL and KLF designed the study. TG and AG performed the analyses. TG, JL, AG, KLF and JOL interpreted the findings. TG and JL wrote the first draft. TG, JL, AG, KLF and JOL contributed to the final draft.

  • Funding This project was supported through funds obtained through a Prevention Innovation Grant from the Canadian Cancer Society (CCS) (#705561, PI: KLF) and the Canadian Institutes of Health Research (#CCP-155425). TG is funded by fellowship awards from the Canadian Institutes of Health Research (CIHR) and the Fonds de Recherche du Québec – Santé (FRQS). JOL holds a Canada Research Chair in the Early Determinants of Adult Chronic Disease. KLF holds a Myriagone UdeM-McConnell Chair in Youth Knowledge Mobilisation. The services and activities provided by the QICSS are made possible by the financial or in-kind support of the Social Sciences and Humanities Research Council (SSHRC), the Canadian Institutes of Health Research (CIHR), the Canada Foundation for Innovation (CFI), Statistics Canada, the Fonds de recherche du Québec - Société et culture (FRQSC), the Fonds de recherche du Québec - Santé (FRQS) and the Quebec universities.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The Health Research Ethics Committee at the University of Montreal granted ethical approval for this study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data may be obtained from a third party and are not publicly available. The analysis presented in this paper was conducted at the Quebec Interuniversity Centre for Social Statistics which is part of the Canadian Research Data Centre Network (CRDCN).