| Ontario | Quebec | p-value# | Total | |
| Occupational asthma | ||||
| 1 year prior | 24/72 (33.33) | 75/192 (39.06) | 99/264 (37.50) | |
| 1 year after | 12/72 (16.67) | 16/192 (8.33) | 28/264 (10.61) | |
| 2 years after | <6/72 | 13/192 (6.77) | Not calculated¶ | |
| 1 year after versus 1 year prior | 0.50 (0.27–0.92) | 0.21 (0.13–0.35) | 0.0372 | 0.28 (0.19–0.41) |
| 2 years after versus 1 year prior | 0.13 (0.04–0.40) | 0.17 (0.10–0.30) | 0.7116 | 0.16 (0.10–0.27) |
| Work-exacerbated asthma | ||||
| 1 year prior | 23/59 (38.98) | 54/242 (22.31) | 77/301 (25.58) | |
| 1 year after | 8/59 (13.56) | 41/242 (16.94) | 49/301 (16.8) | |
| 2 years after | <6/59 | 24/242 (9.92) | Not calculated¶ | |
| 1 year after versus 1 year prior | 0.35 (0.17–0.71) | 0.76 (0.53–1.09) | 0.0383 | 0.64 (0.46–0.88) |
| 2 years after versus 1 year prior | 0.17 (0.06–0.47) | 0.44 (0.28–0.69) | 0.0521 | 0.36 (0.24–0.54) |
Data are presented as n/N (%) or relative risk (95% CI), unless otherwise stated. #: indicating statistical differences between Ontario and Quebec based on Breslow–Day test for homogeneity; ¶: to safeguard data confidentiality due to small number in Ontario.