| Control | Case | χ2 (df = 1) | P |
---|---|---|---|---|
Gender | Â | Â | Â | Â |
 Females | 50 | 45 | 0.58 | 0.443 |
 Males | 68 | 75 |  |  |
Smoking habit | Â | Â | Â | Â |
 Non-smoker | 64 | 68 | 5.76 | 0.016 |
 Smoker | 18 | 42 |  |  |
 Missing | 36 | 10 |  |  |
Workplace | Â | Â | Â | Â |
 Indoor | 66 | 66 | 6.21 | 0.013 |
 Outdoor | 26 | 54 |  |  |
 Missing | 26 | 0 |  |  |
Hypertension | Â | Â | Â | Â |
 No | 105 | 112 | 1.03 | 0.309 |
 Yes | 4 | 8 |  |  |
 Missing | 9 | 0 |  |  |
Age | 63.5 ± 10.0 | 69.9 ± 9.7 | t = 4.76, df = 236 | < 0.001 |