Table 2.
Adjusted mortality rate ratios (MRR)a for lung cancer as function of cumulative exposure to synthetic metalworking fluid (MWF) and years exposed to biocide as estimated by Cox regression nested in the incident hires subcohort of workers hired on or after start of follow-up. [95% CI=95% confidence interval.]
| Deaths (N) | MRR | 95% CI | |
|---|---|---|---|
|
|
|||
| Synthetic MWF (mg/m3 per year)b | |||
| Unexposed | 583 | 1.00 | .. |
| 0–0.27 | 63 | 0.92 | 0.68–1.24 |
| >0.27–0.85 | 64 | 1.14 | 0.84–1.54 |
| >0.85–2.15 | 63 | 0.85 | 0.62–1.16 |
| >2.15 | 64 | 0.79 | 0.59–1.05 |
| Biocide (years exposed with synthetic MWF)b | |||
| Unexposed | 611 | 1.00 | .. |
| 0–0.13 | 56 | 1.07 | 0.79–1.46 |
| >0.13–0.40 | 57 | 1.17 | 0.85–1.59 |
| >0.40–1.04 | 56 | 0.94 | 0.69–1.30 |
| >1.04 | 57 | 1.00 | 0.75–1.35 |
| Biocide (years exposed with soluble MWF)c | |||
| Unexposed | 805 | 1.00 | .. |
| 0–0.66 | 8 | 0.67 | 0.33–1.38 |
| >0.66–1.67 | 8 | 1.01 | 0.49–2.10 |
| >1.67–2.36 | 8 | 1.70 | 0.81–3.55 |
| >2.36 | 8 | 0.62 | 0.30–1.28 |
a
Synthetic MWF, biocide with synthetic MWF, and biocide with soluble MWF were fit in separate models; all models were adjusted for straight MWF, race, gender, plant, calendar year, and years since retirement.
b
Additional adjustments in model for soluble MWF
c
Additional adjustments in model for synthetic MWF