Table 4.
RR of lung cancer mortality 1959–1996 and intensity and years of diesel exposure weighteda cumulative years of work in an engineer or conductor job group, stratified by year of hire (1939–1944 and 1945–1949). Models are adjusted for age, work in any shop category, years of employment and time since last worked as time dependent covariates, and include a 5-year exposure lag.
| Quintiles of “intensity-years” | |||||||
|---|---|---|---|---|---|---|---|
| Hire Date | Not Exposed | Q1 | Q2 | Q3 | Q4 | Q5 | |
| 1939–1949 (all) | Cases | 916 | 410 | 522 | 472 | 507 | 460 |
| Person years | 334,704 | 248,599 | 152,914 | 107,566 | 94,294 | 81,655 | |
| RR | ref | 1.37 | 1.37 | 1.47 | 1.35 | 1.35 | |
| 95% CI | 1.21–1.56 | 1.23–1.53 | 1.32–1.65 | 1.20–1.51 | 1.19–1.53 | ||
| 1939–1944 | Cases | 687 | 326 | 394 | 417 | 427 | 363 |
| Person years | 236,377 | 199,407 | 115,233 | 97,381 | 78,075 | 66,103 | |
| RR | ref | 1.26 | 1.33 | 1.33 | 1.28 | 1.24 | |
| 95% CI | 1.09–1.46 | 1.17–1.51 | 1.17–1.50 | 1.13–1.45 | 1.08–1.43 | ||
| 1945–1949 | Cases | 229 | 80 | 98 | 93 | 76 | 97 |
| Person years | 98,327 | 49,892 | 29,621 | 18,810 | 15,434 | 15,073 | |
| RR | ref | 1.63 | 1.54 | 2.02 | 1.50 | 1.81 | |
| 95% CI | 1.24–2.14 | 1.21–1.96 | 1.58–2.59 | 1.14–1.96 | 1.39–2.35 | ||
a
The intensity score, based on the overall distribution of the EAF, was divided into three groups: <20 μg/hr (group 1), 20-<25 μg/hr (group 2), and ≥25 μg/hr (group 3). For each cohort member, “intensity-years” was calculated by multiplying the year-specific intensity score (1, 2, or 3), and years of diesel exhaust exposure weighted by diesel fraction (DF).