Table 2.
Distribution of selected host characteristics by case–control status in Chinese
| Variables | Case (n = 384) | Control (n = 384) | P* |
|---|---|---|---|
| Age, y (mean ± SD) |
62.4 ± 10.8 |
61.5 ± 12.1 |
0.277 |
| Gender, no. (%) |
|
|
|
| Male |
222 (57.8) |
217 (56.5) |
0.715 |
| Female |
162 (42.2) |
167 (43.5) |
|
| Smoking status, no. (%) |
|
|
|
| Never |
228 (59.4) |
218 (56.8) |
0.738 |
| Former |
70 (18.2) |
72 (18.7) |
|
| Current |
86 (22.4) |
94 (24.5) |
|
| Pack-years (mean ± SD) |
32.7 ± 25.1 |
30.3 ± 27.7 |
0.209 |
| Tumor grade, no. (%) |
|
|
|
| I |
41 (10.7) |
0 |
|
| II |
176 (45.8) |
0 |
|
| III |
86 (22.4) |
0 |
|
| IV | 81 (21.1) | 0 |
*P values were derived from the χ2 test for categorical variables (gender and smoking status) and t test for continuous variables (age and pack-years).