Leukaemia: SIR by workplace type and RIR by period of hire, duration of employment, years since hire, highest hydrocarbon ranking job held, and hydrocarbon ranking of job held longest, adjusted for age, calendar year; RIRs also adjusted for smoking
| Workplace type | Person-years | O/E | SIR | 95% CI |
|---|---|---|---|---|
| Refinery | 69795 | 10/8.1 | 1.24 | 0.59 to 2.27 |
| Terminal | 73373 | 14/8.6 | 1.63 | 0.89 to 2.73 |
| Airport | 6877 | 1/0.8 | 1.24 | 0.03 to 6.92 |
| Onshore production | 19629 | 1/1.5 | 0.66 | 0.02 to 3.67 |
| Offshore production | 6924 | 1/0.5 | 2.15 | 0.05 to 11.97 |
| Period of hire | Person-years | Cases | RIR* | 95% CI |
|---|---|---|---|---|
| Post-1975 | 79838 | 7 | 1 | |
| 1965–74 | 60283 | 8 | 1.11 | 0.36 to 3.39 |
| 1955–64 | 24837 | 5 | 1.51 | 0.34 to 6.69 |
| Pre-1954 | 11640 | 7 | 4.03 | 0.81 to 20.1 |
| Years of employment | Person-years | Cases | RIR† | 95% CI |
|---|---|---|---|---|
| 5–9 | 45836 | 4 | 1 | |
| 10–15 | 43718 | 5 | 1.14 | 0.30 to 4.41 |
| 15–19 | 32976 | 4 | 1.08 | 0.24 to 4.82 |
| 20–24 | 21475 | 4 | 1.53 | 0.32 to 7.32 |
| 25+ | 32593 | 10 | 1.97 | 0.43 to 9.13 |
| Years since hire | Person-years | Cases | RIR‡ | 95% CI |
|---|---|---|---|---|
| 5–9 | 37624 | 4 | 1 | |
| 10–14 | 41147 | 3 | 0.63 | 0.14 to 2.89 |
| 15–19 | 34372 | 3 | 0.69 | 0.14 to 3.51 |
| 20–24 | 23741 | 7 | 2.14 | 0.48 to 9.55 |
| 25+ | 39714 | 10 | 1.33 | 0.26 to 6.88 |
| Highest hydrocarbon ranking job | Person-years | Cases | RIR§ | 95% CI |
|---|---|---|---|---|
| 1 | 33991 | 1 | 1 | |
| 2 | 14986 | 1 | 3.17 | 0.19 to 51.9 |
| 3 | 1912 | 0 | 0 | |
| 4 | 80583 | 16 | 7.14 | 0.94 to 54.1 |
| 5 | 6430 | 1 | 6.65 | 0.41 to 106.7 |
| 6 | 28420 | 6 | 6.9 | 0.82 to 58.0 |
| 7 | 10252 | 2 | 7 | 0.63 to 77.9 |
| Hydrocarbon ranking longest job | Person-years | Cases | RIR¶ | 95% CI |
|---|---|---|---|---|
| Tests for trend—*p = 0.09, †p = 0.34, ‡p = 0.37, §p = 0.05, ¶p = 0.07 | ||||
| 1 | 45922 | 2 | 1 | |
| 2 | 15856 | 1 | 1.79 | 0.16 to 20.1 |
| 3 | 2959 | 0 | 0 | |
| 4 | 74258 | 17 | 4.93 | 1.14 to 21.4 |
| 5 | 4723 | 1 | 5.11 | 0.46 to 56.4 |
| 6 | 25187 | 6 | 4.63 | 0.93 to 23.2 |
| 7 | 5011 | 0 | 0 | |