Table 3.

ORs and 95% CIs for average and cumulative REC and total duration REC exposure for subjects who ever worked underground jobs, DEMS II, United States, 1947–2015, 252 lung cancer deaths and 471 controls.

Exposure metric	Casesa	Controlsa	OR (95% CI)	$p_{\mathrm{t}\mathrm{r}\mathrm{e}\mathrm{n}\mathrm{d}}$
Average REC intensity [quintiles; unlagged (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)]
0 to $<26$	41	73	1.00 (Ref)	0.037
26 to $<62$	41	84	1.07 (0.52, 2.22)
62 to $<121$	41	91	0.90 (0.44, 1.83)
121 to $<168$	41	48	2.30 (1.02, 5.18)
$\ge 168$	41	57	2.15 (0.88, 5.29)
Average REC intensity [quintiles; lagged 15 y (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)]
0 to $<7$	41	87	1.00 (Ref)	0.009
7 to $<47$	41	76	0.82 (0.39, 1.73)
47 to $<93$	41	77	1.31 (0.61, 2.82)
93 to $<162$	41	63	1.40 (0.61, 3.21)
$\ge 162$	41	50	2.98 (1.19, 7.51)
Cumulative REC [quintiles; unlagged (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3\text{-y}$)]
0 to $<198$	41	81	1.00 (Ref)	0.134
198 to $<469$	41	74	1.08 (0.55, 2.11)
469 to $<958$	41	64	1.57 (0.78, 3.18)
958 to $<\mathrm{2,210}$	41	70	1.62 (0.79, 3.31)
$\ge \mathrm{2,210}$	41	64	1.72 (0.83, 3.55)
Cumulative REC [quintiles; lagged 15 y (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3\text{-y}$)]
0 to $<95$	41	106	1.00 (Ref)	0.072
95 to $<276$	41	58	1.25 (0.59, 2.69)
276 to $<675$	41	84	1.63 (0.78, 3.38)
675 to $<\mathrm{1,254}$	41	48	3.83 (1.71, 8.55)
$\ge \mathrm{1,254}$	41	57	2.09 (0.94, 4.66)
Duration of REC exposure (y)
$<5$	70	132	1.00 (Ref)	0.052
$5\text{\hspace{0.17em}to}<10$	29	54	1.20 (0.64, 2.27)
$10\text{\hspace{0.17em}to}<15$	37	65	1.20 (0.63, 2.27)
$15+$	69	102	1.77 (1.00, 3.11)

Note: $p$-Values based on two-sided Wald test for linear trend (Supplementary Table S8). Adjusted for smoking status (never smoker, unknown/occasional smoker, former $\text{smoker}/<1$ pack/day, former smoker/1 to $<2$ packs/day, former $\text{smoker \hspace{0.17em}}/\ge 2$ packs/day, current $\text{smoker}/<1$ pack/day, current smoker/1 to $<2$ packs/day, current $\text{smoker}/\ge 2$ packs/day); history of respiratory disease 5 or more years before date of death/reference date; history of a high-risk job for lung cancer for at least 10 y; and BMI. BMI, body mass index; CI, confidence interval; DEMS, Diesel Exhaust in Miners Study; OR, odds ratio; REC, respirable elemental carbon; Ref, referent.

^a A total of 47 cases and 183 controls were excluded because they no longer belonged to a complete matched set after analysis was restricted to underground workers.