. 2010 Oct 7;32(1):69–73. doi: 10.1093/carcin/bgq204

Table II.

Baseline characteristics of lung cancer cases and controls nested within the PLCO Cancer Screening Trial

Characteristic at the time of blood collection	Controls (n = 117), N %		Cases (n = 117), N %		P-value
Age in years^a
55–64	30	25.6	30	25.6	1.00
65–69	37	31.6	37	31.6
70–79	50	42.7	50	42.7
Gender^a
Male	81	69.2	81	69.2	1.00
Female	36	30.8	36	30.8
Cigarette smoking status^a
Never smoked cigarettes^b	7	6.0	7	6.0	1.00
Quit 10+ years ago and cigarettes/day ≤ 1 pack	8	6.8	8	6.8
Quit 10+ years ago and cigarettes/day > pack	27	23.1	27	23.1
Current or quit <10 years ago and cigarettes/day ≤ 1 pack	39	33.3	39	33.3
Current or quit <10 years ago and cigarettes/day > 1 pack	36	30.8	36	30.8
Race
White, non-Hispanic	112	95.7	109	93.2
Nonwhite or Hispanic	5	4.3	8	6.8	0.39
Education
≤11 years	12	10.3	13	11.1	0.70
12 years or completed high school	23	19.7	28	23.9
Post-high school other than college or some college	41	35.0	43	36.8
College graduate or postgraduate	41	35.0	33	28.2
Lung cancer reported in first-degree relatives^c
No	97	84.3	98	84.5	0.64
Yes	15	13.0	13	11.2
Unknown	3	2.6	5	4.3
History of emphysema^c
No	104	92.0	96	88.9	0.43
Yes	9	8.0	12	11.1
Months between blood collection and lung cancer diagnosis					NA
3–11	NA		24	20.5
12–23	NA		28	23.9
24–35	NA		26	22.2
36–47	NA		24	20.5
48+	NA		15	12.8
Lung cancer histology
Adenocarcinoma	NA		39	33.3	NA
Squamous	NA		27	23.1
Small cell	NA		21	17.9
Non-small cell, not otherwise specified	NA		8	6.8
Large cell	NA		7	6.0
Other^d	NA		15	12.8

NA is not applicable.

Matching variables.

Two cases and one control reported having smoked cigars but not cigarettes.

May not sum to 117 cases or 117 controls due to missing data.

Four cases bronchioalveolar adenocarcinoma, two cases acinar adenocarcinoma, two cases carcinoma not otherwise specified, one case intermediate cell carcinoma, one case adenosquamous carcinoma and five cases not available.