Table 1.

Selected Study Population Characteristics by Lung Cancer Status and Silica Exposure

Characteristic	Ever Exposed to Silica				Never Exposed to Silica
	Cases (n)	%	Control Subjects (n)	%	Cases (n)	%	Control Subjects (n)	%
Sex
M	4,649	94.4		4,140	92.2	8,956	74.8	12,311	74.7
F	274	5.6		348	7.8	3,022	25.2	4,166	25.3
Age group
<45 yr	142	2.9		194	4.3	573	4.8	1,177	7.1
45–64 yr	2,503	50.8		2,055	45.8	6,260	52.3	8,299	50.4
>64 yr	2,278	46.3		2,239	49.9	5,145	43.0	7,001	42.5
Smoking status
Never-smoker	248	5.0		1,253	27.9	1,121	9.4	5,900	35.8
Former smoker	1,736	35.3		2,010	44.8	3,696	30.9	6,210	37.7
Current smoker	2,939	59.7		1,225	27.3	7,161	59.8	4,367	26.5
Smoking pack-years
Never-smoker	248	5.0		1,253	27.9	1,121	9.4	5,900	35.8
<10	227	4.6		683	15.2	582	4.9	2,386	14.5
10–19	475	9.6		598	13.3	1,127	9.4	2,264	13.7
>19	3,973	80.7		1,954	43.5	9,148	76.4	5,927	36.0
Years since quitting smoking
Never-smoker	248	5.0		1,253	27.9	1,121	9.4	5,900	35.8
>0–7 yr	638	13.0		317	7.1	1,388	11.6	1,105	6.7
8–15 yr	494	10.0		461	10.3	1,037	8.7	1,437	8.7
16–25 yr	379	7.7		590	13.1	792	6.6	1,756	10.7
>25 yr	225	4.6		642	14.3	479	4.0	1,912	11.6
Current smoker	2,939	59.7		1,225	27.3	7,161	59.8	4,367	26.5
List A job
Ever employment	829	16.8		597	13.3	958	8.0	767	4.7
Never employment	4,094	83.2		3,891	86.7	10,905	92.0	15,563	95.3
Silicosis
Reported silicosis	57	1.2		33	0.7	13	0.1	5	0
No reported silicosis	2,882	58.5		2,311	51.5	6,091	50.9	7,539	45.8
Unknown	1,984	40.3		2,144	47.8	5,874	49.0	8,933	54.2
Lung cancer subtype
Adenocarcinoma	1,069	21.7		—	—	3,683	30.7	—	—
Small cell carcinoma	869	17.7		—	—	1,861	15.5	—	—
Squamous cell carcinoma	2,251	45.7		—	—	4,252	35.5	—	—
Other/unspecified	711	14.4		—	—	2,111	17.6	—	—
Not available	23	0.5		—	—	71	0.6	—	—