Table 1 Distribution of selected characteristics among PTC cases and controls.
Variable | Zhejiang case-control set (Discovery set) | Jiangsu case-control set (Validation set 1) | Jilin case-control set (Validation set 2) | ||||||
|---|---|---|---|---|---|---|---|---|---|
Cases | Controls | P -value a | Cases | Controls | P -value a | Cases | Controls | P -value a | |
No. (%) | No. (%) | No. (%) | No. (%) | No. (%) | No. (%) | ||||
| Â | 500 | 500 | Â | 1000 | 1000 | Â | 800 | 800 | Â |
Sex | Â | Â | 0.560 | Â | Â | 0.223 | Â | Â | 0.774 |
 Male | 122(24.4) | 130(26.0) |  | 251(25.1) | 275(27.5) |  | 200(25.0) | 205(25.6) |  |
 Female | 378(75.6) | 370(74.0) |  | 749(74.96) | 725(72.5) |  | 600(75.0) | 595(74.4) |  |
Age (year)2 | Â | Â | 0.486 | Â | Â | 0.823 | Â | Â | 0.453 |
 ≤46(or 48) | 258(51.6) | 269(53.8) |  | 526(52.6) | 521(52.1) |  | 411(51.4) | 426(53.2) |  |
 >46(or 48) | 242(48.4) | 231(46.2) |  | 474(47.4) | 479(47.9) |  | 389(48.6) | 374(46.8) |  |
