| Cigarette smoking status/occupational exposure | Total number of subjects (COPD + referent) | Probability of COPD | Excess probability* | Crude OR | Adjusted OR |
| Entire FLOW cohort | |||||
| Never/no | 178 | 0.44 | 0 | 1.0 | 1.0 |
| Never/yes | 145 | 0.60 | 0.16 | 1.92 (1.23 to 3.00) | 1.98 (1.26 to 3.09) |
| Ever/no | 512 | 0.83 | 0.40 | 6.44 (4.42 to 9.39) | 6.71 (4.58 to 9.82) |
| Ever/yes | 669 | 0.91 | 0.47 | 13.3 (8.90 to 19.8) | 14.1 (9.33 to 21.2) |
| GOLD stage II or higher | |||||
| Never/no | 136 | 0.26 | 0 | 1.0 | 1.0 |
| Never/yes | 94 | 0.38 | 0.12 | 1.72 (0.98 to 3.03) | 1.69 (0.96 to 2.97) |
| Ever/no | 349 | 0.76 | 0.49 | 8.63 (5.49 to 13.6) | 8.31 (5.27 to 13.1) |
| Ever/yes | 465 | 0.87 | 0.61 | 19.1 (12.0 to 30.5) | 18.7 (11.6 to 30.0) |
COPD, chronic obstructive pulmonary disease; FLOW, Function, Living, Outcomes and Work study; GOLD, Global Obstructive Lung Disease initiative.
*Difference in unadjusted probability of COPD compared with referent group (rounding error accounts for lack of agreement in some cells).
Adjusted odds ratio controls for age, sex and race in addition to smoking status.