. Author manuscript; available in PMC: 2014 Jul 23.

Published in final edited form as: Scand J Work Environ Health. 2010 Sep 13;36(6):499–508. doi: 10.5271/sjweh.3088

Table 4.

Adjusted mortality rate ratios (MRR)^a for lung cancer as function of cumulative exposure to synthetic metalworking fluid (MWF) as estimated by Cox regression nested in the incident hires subcohort of workers hired on or after start of follow-up during the early and extended follow-up periods. [95% CI=95% confidence intervals.]

Synthetic MWF (mg/m³ per year)^b	Previous follow-up (1941–1984)			Extended follow-up (1985–1994)
	N deaths	MRR	95% CI	N deaths	MRR	95% CI
Unexposed	309	1.00	..	274	1.00	..
0–0.23, 0–0.28	26	0.73	0.49–1.15	37	1.10	0.73–1.67
>0.23–0.84, 0.28–0.88	27	0.78	0.49–1.23	37	1.29	0.85–1.96
>0.84–1.93, 0.88–2.28	26	0.70	0.44–1.12	37	1.23	0.81–1.86
>1.93, >2.28	27	0.45	0.29–0.71	37	0.97	0.66–1.43

Cox models were adjusted for straight MWF, soluble MWF, race, gender, plant, calendar year, and years since retirement.

Exposure cut-offs for increasing quartile of cumulative exposure to total mass particulate metalworking fluid (mg/m³ per year) determined by distribution of exposed cases; first and second exposure intervals listed reflect previous and extended follow-up periods, respectively.