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The characteristics of case group and control group
| Characteristics | Case group (n = 231) | Control group (n = 370) | P value |
|---|---|---|---|
| Age (years) | 48.40 ± 11.66 | 47.85 ± 12.30 | 0.591 |
| Smoking | 55 (23.8 %) | 79 (21.4 %) | 0.481 |
| Gender (female/male) | 95/136 | 175/195 | 0.139 |
