Demographic and exposure characteristics of lung cancer cases and non-cases in a cohort of diatomaceous earth workers exposed to silica
| Lung cancer cases | Non-cases | |
|---|---|---|
| *Time varying covariates were computed for each subject at the end of follow up. | ||
| †534 subjects were not eligible for risk sets because they either died or were censored at an earlier age than the minimum age of lung cancer death. | ||
| Number of subjects | 77 | 2265† |
| Hispanic ethnicity; n (%) | 4 (5.2%) | 542 (23.9%) |
| Calendar year of death; mean (SD) | 1978 (10.4) | |
| Year of hire; mean (SD) | 1944 (10.9) | 1954 (14.0) |
| Age at hire; mean (SD) | 30.4 (9.3) | 26.7 (8.0) |
| Duration of follow up (y)*; mean (SD) | 30.1(9.9) | 28.1 (14.5) |
| Duration of work (y)*; mean (SD) | 13.6 (13.3) | 10.7 (11.4) |
| Cumulative silica exposure (mg/m3-y)* | ||
| Mean (SD) | 4.3 (5.8) | 2.1 (3.4) |
| 50th centile | 2.3 | 1.1 |
| 75th centile | 5.8 | 2.4 |
| 99th centile | 32.1 | 15.7 |
| Maximum | 32.1 | 62.6 |