Table 1.
Distribution of selected host characteristics by case–control status in Chinese
| Variables | Case (n = 384) | Control (n = 384) | Pb |
|---|---|---|---|
| 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. (%) |
|
|
|
| No |
228 (59.4) |
218 (56.8) |
0.465 |
| Yes |
156 (40.6) |
166 (43.2) |
|
| Pack-years (mean ± SD)a |
32.7 ± 25.1 |
30.3 ± 27.7 |
0.209 |
| Drinking status, no. (%) |
|
|
|
| No |
288 (75.0) |
273 (71.1) |
0.222 |
| Yes |
96 (25.0) |
111 (28.9) |
|
| WHO grade, no. (%) |
|
|
|
| WHO I |
41 (10.7) |
|
|
| WHO II |
176 (45.8) |
|
|
| WHO III |
86 (22.4) |
|
|
| WHO IV | 81 (21.1) |
aAmong ever smokers.
bP values were derived from the χ2 test for categorical variables (gender, smoking and drinking status) and t test for continuous variables (age and pack-years).