. 2020 Aug 1;202(3):402–411. doi: 10.1164/rccm.201911-2101OC

Table 2.

Lung Cancer ORs Associated with Categorical Indices of Occupational EC Exposure

Occupational EC Exposure	Cases, n (%)	Controls, n (%)	OR^*	95% CI
Men
Never	5,560 (40.9)	8,270 (50.3)	1.0	Referent

Ever exposure	8,045 (59.1)	8,181 (49.7)	1.22	1.15–1.29

Duration, yr
1–9	2,346 (17.2)	2,750 (16.7)	1.07	1.00–1.16
10–19	1,774 (13.0)	1,774 (10.8)	1.23	1.13–1.34
20–29	1,578 (11.6)	1,471 (8.9)	1.23	1.12–1.35
>29	2,347 (17.3)	2,186 (13.3)	1.39	1.28–1.51
Test for trend, P value^†	—	—	<0.01	—
P value excluding never exposed^‡	—	—	<0.01	—

Cumulative exposure, μg/m³-years
>0–22	1,684 (12.4)	2,002 (12.2)	1.09	1.00–1.19
23–70	1,858 (13.7)	2,005 (12.2)	1.10	1.02–1.20
71–178	2,113 (15.5)	2,074 (12.6)	1.24	1.15–1.35
>178	2,390 (17.6)	2,100 (12.8)	1.43	1.32–1.54
Test for trend, P value^†	—	—	<0.01	—
P value excluding never exposed^‡	—	—	<0.01	—


Women
Never	2,910 (88.3)	4,002 (88.7)	1.0	Referent

Ever exposure	386 (11.7)	512 (11.3)	1.00	0.85–1.18

Duration, yr
1–9	235 (7.1)	273 (6.0)	1.02	0.83–1.26
10–19	86 (2.6)	112 (2.5)	1.07	0.77–1.47
20–29	25 (0.8)	49 (1.1)	0.69	0.39–1.17
>29	40 (1.2)	78 (1.7)	1.05	0.69–1.58
Test for trend, P value^†	—	—	0.85	—
P value excluding never exposed^‡	—	—	0.74	—

Cumulative exposure, μg/m³-years
>0–22	165 (5.0)	179 (4.0)	1.03	0.80–1.33
23–70	118 (3.6)	162 (3.6)	1.03	0.78–1.36
71–178	64 (1.9)	99 (2.2)	0.92	0.64–1.31
>178	39 (1.2)	72 (1.6)	0.97	0.62–1.48
Test for trend, P value^†	—	—	0.99	—
P value excluding never exposed^‡	—	—	0.82	—

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

ORs are adjusted for study, age group, smoking pack-years [log(cigarette pack-years + 1)], time since quitting smoking, and list A jobs.

^{^†}

Test for trend, P value obtained using the corresponding continuous exposure variable.

^{^‡}

Test for trend, P value obtained using the corresponding continuous exposure variable among exposed subjects only.