Table 3. Patient characteristics of major subgroups.

Variable	Smoking at initial scan (n=678)	Quit at initial scan (n=783)	P
Smoking at most recent scan	537	73
Quit at most recent scan	141	710
Age (years)	61.3±5.91	63.6±5.82	<0.001
Pack year history	47.8±20.1	50.0±23.2	0.056
Duration in program (years)	1.43±0.63	1.46±0.64	0.35
Number of positive scans	0.80±1.09	0.85±1.20	0.42
Male	386 (56.9%)	393 (50.2%)	0.01
Female	292 (43.1%)	390 (49.8%)
Group 1	560 (82.6%)	545 (69.6%)	<0.001
Group 2	118 (17.4%)	238 (30.4%)
Prior history of cancer	122 (18.0%)	127 (16.2%)	0.37
Outside referring PCP	113 (16.7%)	142 (18.1%)	0.46
3+ scans	335 (49.4%)	401 (51.2%)	0.49
1+ positive scans	257 (37.9%)	288 (36.8%)	0.66
Negative initial scan	479 (70.6%)	560 (71.5%)	0.71
S positive	40 (5.9%)	48 (6.1%)	0.85

Values are reported as mean ± standard deviation. Values in () percent of sample.