Table 1. Characteristics of lung cancer cases, hospital, and population controls
|
Cases, n = 443 (%) |
Total controls, n = 547 (%) |
Hospital controls, n = 240 (%) |
Population controls, n = 307 (%) |
|
| Age (mean ± SD) |
65.7 ± 10.3 |
64.8 ± 10.9 |
63.1 ± 12.1* |
66.2 ± 9.7 |
| Gender |
| Male |
220 (50) |
261 (48) |
112 (47) |
149 (49) |
| Female |
223 (50) |
286 (52) |
128 (53) |
158 (52) |
| Race |
| African American |
120 (27) |
204 (37) |
77 (32) |
127 (41) |
| Caucasians |
323 (73) |
343 (63) |
163 (68) |
180 (59) |
| Smoking status |
| Never |
35 (8) |
175 (32) |
53 (22) |
122 (40) |
| Former |
192 (43) |
264 (49) |
119 (50) |
145 (48) |
| Current |
215 (49) |
105 (19) |
67 (28) |
38 (12) |
| Pack-years (mean ± SD) |
41.5 ± 28.3 |
23.3 ± 28.5 |
34.6 ± 33.7 |
14.3 ± 19.5 |
|
* Hospital controls were younger than cases (P = 0.005, t test for unequal variances).
The race distribution was different in total controls (P = 0.001, 
2 test) and population controls (P < 0.0001, 2 test) compared with lung cancer cases.
The distribution of smoking status differed in total controls, hospital controls, and population controls (P < 0.0001, 2 test) compared with lung cancer cases.
Total controls, population controls (P < 0.0001, t test for unequal variances), and hospital controls (P = 0.007, t test for unequal variances) smoked fewer pack-years than lung cancer cases.