TABLE 3.

LUNG CANCER RISK ASSOCIATED WITH CUMULATIVE DIESEL MOTOR EXHAUST EXPOSURE

Subjects	Cumulative Diesel Motor Exhaust Exposure (unit-years)*	Cases	%	Controls	%	OR1†	95% CI	OR2‡	95% CI
All	Never	7,676	57.7	10,320	63.4	1.00	Reference	1.00	Reference
	<6	1,269	9.5	1,513	9.3	1.04	0.96–1.13	0.98	0.89–1.08
	6–17.33	1,325	10	1,497	9.2	1.13	1.04–1.23	1.04	0.95–1.14
	17.34–34.5	1,440	10.8	1,502	9.2	1.23	1.13–1.33	1.06	0.97–1.16
	>34.5	1,594	12	1,450	8.9	1.42	1.31–1.54	1.31	1.19–1.43
	Test for trend, P value									<0.01§			<0.01§
Women	Never	2,144	86	2,810	86.4	1.00	Reference	1.00	Reference
	<6	146	5.9	198	6.1	0.85	0.68–1.07	0.83	0.64–1.08
	6–17.33	116	4.7	127	3.9	1.07	0.82–1.39	1.27	0.94–1.71
	17.34–34.5	51	2	71	2.2	0.87	0.60–1.26	0.94	0.62–1.42
	>34.5	35	1.4	45	1.4	1.03	0.66–1.63	1.58	0.96–2.59
	Test for trend, P value									0.83§			0.20§
Never-smokers	Never	614	76.7	3,486	73	1.00	Reference	N/A
	<6	44	5.5	334	7	0.74	0.52–1.05
	6–17.33	63	7.9	328	6.9	1.22	0.90–1.65
	17.34–34.5	33	4.1	305	6.4	0.85	0.57–1.26
	>34.5	47	5.9	320	6.7	1.26	0.90–1.78
	Test for trend, P value									0.28§
Workers never employed in a “List A” job	Never	6,954	59.4	9,764	65	1.00	Reference	1.00	Reference
	<6	1,034	8.8	1,320	8.8	1.05	0.96–1.15	0.98	0.89–1.09
	6–17.33	1,091	9.3	1,309	8.7	0.15	1.06–1.26	1.07	0.97–1.18
	17.34–34.5	1,223	10.4	1,324	8.8	1.28	1.17–1.39	1.10	1.00–1.21
	>34.5	1,412	12.1	1,301	8.7	1.49	1.37–1.62	1.35	1.23–1.49
	Test for trend, P value									<0.01§		<0.01§

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

^*The categories represent the quartile distribution of cumulative diesel motor exhaust exposure among exposed controls.

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

^‡OR2 is additionally adjusted for pack-years and time-since-quitting smoking.

^§Test for trend, P value obtained using the continuous variable for cumulative exposure.