Table 1 The distribution of demographic variables among the never smoking cases and controls
Demographic variables | Controls N (%) | Cases N (%) | χ2 | p |
|---|---|---|---|---|
Sex | Â | Â | Â | Â |
 Male | 153 (19.9%) | 153 (19.9%) |  |  |
 Female | 614 (80.1%) | 614 (80.1%) |  |  |
Age (years) | Â | Â | 0.066 | 0.967 |
 50 | 202 (26.3%) | 205 (26.7%) |  |  |
 50–65 | 376 (49.0%) | 377 (49.2%) |  |  |
 65 | 189 (24.6%) | 185 (24.1%) |  |  |
Marriage | Â | Â | 1.337 | 0.248 |
 Married | 704 (91.8%) | 691 (90.1%) |  |  |
 Unmarried/divorced | 63 (8.2%) | 76 (9.9%) |  |  |
Education |  |  | 82.993 |  < 0.001 |
 Primary school and below | 260 (33.9%) | 424 (55.3%) |  |  |
 Middle school | 328 (42.8%) | 261 (34.0%) |  |  |
 College and above | 179 (23.3%) | 82 (10.7%) |  |  |
Occupation |  |  | 74.868 |  < 0.001 |
 Mental worker | 367 (47.8%) | 215 (28.0%) |  |  |
 Manual worker | 324 (42.2%) | 395 (51.5%) |  |  |
 Unemployed / unknown | 76 (9.9%) | 157 (20.5%) |  |  |