Abstract

Background

Secondhand smoke exposure (SHSe) is associated with numerous adverse health effects and is a major burden for those who do not smoke. SHSe has been primarily characterized via questionnaire, but exposure levels can also be estimated using a specific biomarker, such as cotinine (COT).

Data and methods

Urinary COT measurements and questionnaire data from three cycles (2007 to 2013) of the Canadian Health Measures Survey were combined and analyzed as indicators of regular SHSe for nonsmokers aged 6 to 79 years. Exposure extent was examined by demographic and socioeconomic variable, dwelling type, and exposure location.

Results

Among Canadian nonsmokers, 22% reported having been regularly exposed to smoke; of those, 26% had detectable COT. The range of SHSe significantly differed by age group and exposure location. While the most frequently reported location category was “outside their home” (16%), the most important contributor to elevated COT was exposure “at home”. The creatinine-adjusted COT geometric mean (C_COT-GM) for the nonsmokers aged 6 to 79 reporting regular home exposure was 3.7 μg/g, but the C_COT-GM was almost three times higher for those living in an apartment than for those in a single-detached home. Some discrepancy appeared between self-reported SHSe and detectable COT estimates for the assessed subpopulations.

Interpretation

Surveillance by questionnaire and biomonitoring both have their own advantages and are fundamental in identifying the subpopulations most susceptible to SHSe. Using a biomarker provides a quantitative estimate of relative exposure that can be compared over time and with other studies, and this is of particular interest for effective public health interventions.

Keywords

Secondhand smoke exposure, questionnaire, biomonitoring, urinary cotinine, population, self-report, Canadian Health Measures Survey

DOI: https://www.doi.org/10.25318/82-003-x202100200002-eng

Findings

Exposure to tobacco smoke has been associated with adverse health effects, and there is no risk-free level of secondhand smoke exposure (SHSe). As a result, steps are being taken to reduce the prevalence of tobacco use and SHSe. [Full article]

Authors

Johanne Levesque (johanne.levesque2@canada.ca) is with the Environmental Health Science and Research Bureau at Health Canada, Ottawa, Ontario, Canada. Trevor Mischki is with the Tobacco Control Directorate at Health Canada, Ottawa, Ontario, Canada.

 

What is already known on this subject?

  • There is no risk-free level of secondhand smoke exposure (SHSe), which has been mainly assessed by questionnaire.
  • Cotinine is a specific biomarker of SHSe.
  • Quantitative biomonitoring SHSe estimates have not been available at the national level for the Canadian population.

What does this study add?

  • This study provided baseline smoke exposure levels in Canada, which can be used for comparisons over time or with other studies.
  • This study identified differences in smoke exposure between various subpopulations, using biomonitoring and questionnaire approaches.
  • This study found based on a biomarker (cotinine) that Canadian nonsmokers living in apartments and aged 6 to 19 were the subpopulations with the highest SHSe. SHSe discrepancies by age groups were also identified for respondents who reported no exposure.

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