Table 2.

Clinical characteristics among 351 cases and controls.

	Cases (n = 166)	Controls (n = 185)	Statistic	p-value
Age (years)	66.93	56.40	t-test	1.23E−15
Gender (% male)	48.80	49.73	chi-square	0.86
Smoking Status (%)	overall		chi-square	1.51E−10
Current	43.37	20.54
Former	47.59	41.62
Never	9.04	37.84
Pack Years	43.43	19.21	t-test	3.12E−09
Quit Years (former smokers)	7.33	9.40	t-test	6.00E−03
Pack years-Quit Years	31.14	5.82	t-test	7.32E−06
Tumor Histology (%)			N/A
Adeno	50.0	N/A
Squam	21.1	N/A
Undiff NSCLC	15.7	N/A
Small Cell	9.0	N/A
Mets/Other	4.2	N/A
Stage (%)			N/A
I	33.13	N/A
II	12.05	N/A
III	31.33	N/A
IV	11.45	N/A
ULD (%)
COPD	56.02	19.46	Fisher	1.29E−12
Fibrosis	1.20	2.16	Fisher	0.69
Inflammation, NOS	1.20	10.27	Fisher	2.16E−04
Asthma	12.05	16.76	Fisher	0.23
Sarcoid	1.20	8.65	Fisher	1.30E−03
Bronchiectasis	2.41	2.70	Fisher	1.00
None	31.33	49.19	Fisher	7.00E−04

Clinical characteristics of the case versus control subjects. Former smoker, defined as quit > 1 year; COPD, defined clinically (MD report, medications), radiographically, and/or pathologically (where available) in medical records; Pack-yrs – Quit-yrs, in former smokers, a constructed composite tobacco exposure risk variable combining cumulative dose (pack years) minus proximity/recency of smoking (quit-years); NOS, not otherwise specified. Adeno = adenocarcinoma; Squamous = squamous cell carcinoma; NSCLC-Undifferentiated non-small cell lung cancer; Small cell = small cell carcinoma; Mets/Other = metastases from other organs to lung or other tumor histologies. ULD = Underlying (chronic) lung disease.