Table 4

Estimated bias in the RR of mortality for a 10 μg/m3 increase in fine particulate matter (PM2.5) in Canada due to differences in smoking prevalence

OutcomeReferenceRR of mortality by smoking statusEstimated bias (%)* and CI
Current relative to neverFormer relative to neverBias95% CI
Lung cancerMalarcher et al3419.607.26−6.93(−2.84 to −11.03)
Coronary heart diseaseMalarcher et al342.801.55−3.18(−1.21 to −5.15)
Cerebrovascular diseaseMalarcher et al343.821.19−2.60(0.40 to −5.61)
Lung cancerGandini et al358.963.95−6.18(−3.45 to −9.63)
  • * Based on a linear regression of percentage change in mortality (dependent variable) against mean PM2.5 (independent variable) observed across the decile exposure categories (see table 3).

  • RRs were weight by the age-sex structure of the CCHS participants.