| Confounding factors | Case (n = 391) | Control (n = 672) | P* value |
| Gender (male/female) | 153/238 | 309/363 | 0.03 |
| Age (year) | 56.98 ± 9.48 | 47.08 ± 10.21 | 0.00 |
| Smoking (%) | 15.9 | 21.1 | 0.04 |
| Alcohol consumption (%) | 43.2 | 65.8 | 0.00 |