TABLE 4.

LUNG CANCER RISK BY YEARS AMONG WORKERS ONLY EXPOSED TO LOW LEVELS OF DIESEL MOTOR EXHAUST EXPOSURE

Duration of Diesel Motor Exhaust Exposure (yrs)	Case/Control	OR1*	95% CI	OR2†	95% CI
0	7,676/ 10,320	1.00	Reference	1.00	Reference
1–10	1,576/1,897	1.05	0.97–1.13	1.00	0.92–1.09
11–20	785/937	1.08	0.98–1.20	0.98	0.88–1.10
21–30	660/723	1.18	1.06–1.33	1.03	0.91–1.17
>30	1,246/1,292	1.28	1.18–1.40	1.17	1.07–1.29
Test for trend, P value		<0.01‡		<0.01‡

Definition of abbreviations: CI = confidence interval; OR = odds ratio.

^*OR1 is adjusted for age, sex, study, and ever-employment in a “List A” job (see text for details).

^†OR2 is additionally adjusted for smoking pack-years, time-since-quitting smoking.

^‡Test for trend, P value obtained by using respective continuous variable.