Table 6

Independent and joint associations of smoking and occupation with chronic obstructive pulmonary disease (COPD)

Cigarette smoking status/occupational exposureSubjects nProbability of COPDExcess#Crude ORAdjusted OR (95% CI)
Any COPD +
Never/no5890.081.01.0
Never/yes2250.100.021.21.4 (0.8–2.3)
Ever/no7280.190.112.62.8 (2.0–3.9)
Ever/yes5190.320.235.06.2 (4.3–9.0)
COPD or emphysema §
Never/no5490.021.01.0
Never/yes2100.040.022.12.4 (0.9–6.1)
Ever/no6590.110.096.57.0 (3.6–13.7)
Ever/yes4540.220.2015.018.4 (9.3–36.4)
  • #: difference in unadjusted probability of COPD between given exposure level and reference group

  • rounding error accounts for lack of agreement in some cells

  • : adjusted for age, sex, race and ethnicity

  • +: reported physician diagnoses of emphysema, COPD and/or chronic bronchitis with or without a concomitant diagnosis of asthma

  • §: narrower definition of COPD, excluding those with chronic bronchitis alone