Secondhand smoke exposure among Canadians: cotinine and self-report measures from the Canadian Health Measures Survey 2007-2009.

INTRODUCTION: Secondhand smoke (SHS) exposure is associated with numerous adverse health effects, including cancer, cardiovascular disease, asthma, respiratory infections, and decreased pulmonary function. This study provides population estimates of SHS exposure among the Canadian nonsmoking population based on self-report and urinary cotinine concentrations. METHODS: The 2007-2009 Canadian Health Measures Survey, a nationally representative cross-sectional survey, collected data from Canadians aged 6-79 years, and it includes self-report and urinary cotinine measures of tobacco smoke exposure (n = 4,455). RESULTS: An estimated 22% of nonsmokers reported being exposed to SHS every day or almost every day. Of those, 70% of children (6-11 years) and 48% of adolescents (12-19 years) had detectable cotinine levels compared with 23% of adults (20-79 years). An estimated 77% of nonsmokers exposed to SHS only in the home had detectable cotinine levels compared with 11% of nonsmokers exposed to SHS only outside the home. Of those exposed to SHS only in the home, a higher percentage of children (5.1%) had detectable cotinine levels compared with adults (3.1%). CONCLUSIONS: Despite well-known health risks associated with exposure to tobacco smoke, a substantial proportion of the Canadian population continues to be exposed to SHS. Higher percentages of certain subpopulations had detectable cotinine concentrations, including children, adolescents, and those exposed to SHS in the home.

Assessment of validity of self-reported smoking status.

BACKGROUND: Cigarette smoking is associated with adverse health effects, including cancer, respiratory illness, heart disease and stroke. National data on smoking prevalence often rely on self-reports. This study assesses the validity of self-reported cigarette smoking status among Canadians. DATA AND METHODS: Data are from the 2007 to 2009 Canadian Health Measures Survey, a nationally representative cross-sectional survey of 4,530 Canadians aged 12 to 79. The survey included self-reported smoking status and a measure of urinary cotinine, a biomarker of exposure to tobacco smoke. The prevalence of cigarette smoking was calculated based on self-reports and also on urinary cotinine concentrations. RESULTS: Compared with estimates based on urinary cotinine concentration, smoking prevalence based on self-report was 0.3 percentage points lower. Sensitivity estimates (the percentage of respondents who reported being smokers among those classified as smokers based on cotinine concentrations) were similar for males and females (more than 90%). Although sensitivity tended to be lower for respondents aged 12 to 19 than for those aged 20 to 79, the difference did not attain statistical significance. INTERPRETATION: Accurate estimates of the prevalence of cigarette smoking among Canadians can be derived from self-reported smoking status data.