Overall and zone specific rate ratio estimates for mesothelioma by years of employment in taconite
| Cases | Controls | RR* | 95% CI | |
|---|---|---|---|---|
| Taconite years | 57 | 184 | 1.03 | 1.00 to 1.06 |
| Haematite years† | 48 | 212 | 0.99 | 0.94 to 1.04 |
| High vs low employment‡ | ||||
| <6.74 years | 26 | 92 | 1.00 | |
| ≥6.74 years | 31 | 92 | 1.23 | 0.67 to 2.28 |
| Haematite only | 23 | 131 | 0.59 | 0.30 to 1.14 |
| Years employment tertiles§ | ||||
| <1.65 years (REF) | 13 | 61 | 1.00 | |
| ≥1.65<12.91 years | 23 | 61 | 1.90 | 0.86 to 4.20 |
| ≥12.91 years | 21 | 62 | 1.62 | 0.73 to 3.58 |
| Haematite only | 23 | 131 | 0.78 | 0.36 to 1.72 |
| Employment by geological zone¶ | ||||
| Zone 1 taconite years | 18 | 74 | 1.05 | 1.00 to 1.11 |
| Zone 2 taconite years | 31 | 58 | 1.06 | 1.02 to 1.09 |
| Zone 4 taconite years | 12 | 66 | 0.97 | 0.92 to 1.03 |
*Rate ratio; adjusted for age, and years of employment in haematite.
†Years in haematite include those employed in haematite only and in both taconite and haematite.
‡High group represents workers with employment duration greater than the control median duration.
§Based on lower, middle, and upper third of control employment duration distribution.
¶Results adjusted for age, employment in haematite, and employment in other zones. Cases and controls may have worked in more than one zone.
REF, referent comparison group.