Table 1. Main characteristics of case and control subjects.
| Variables | Cases (%) (n = 930) | Controls (%) (n = 2667) | χ2 | P-value |
|---|---|---|---|---|
| Age (years) | 0.017 | 0.897 | ||
| ≤ 60 | 510 (54.84) | 1456 (54.59) | ||
| > 60 | 420 (45.16) | 1211 (45.41) | ||
| Gender | 0.003 | 0.955 | ||
| Male | 588 (63.23) | 1689 (63.33) | ||
| Female | 342 (36.77) | 978 (36.67) | ||
| Education level | 5.117 | 0.077 | ||
| Illiterate | 108 (11.61) | 313 (11.74) | ||
| Primary and middle school | 579 (62.26) | 1557 (58.38) | ||
| High school and above | 243 (26.13) | 797 (29.88) | ||
| Residence | 3.475 | 0.062 | ||
| Rural | 523 (56.24) | 1593 (59.73) | ||
| Urban | 407 (43.76) | 1074 (40.27) | ||
| BMI (kg/m2)a | 112.477 | < 0.001 | ||
| 18.5–23.9 | 591 (63.55) | 1499 (56.20) | ||
| < 18.5 | 125 (13.44) | 145 (5.44) | ||
| ≥ 24 | 214 (23.01) | 1023 (38.36) | ||
| Family history of cancer | 18.726 | < 0.001 | ||
| No | 774 (83.23) | 2366 (88.71) | ||
| Yes | 156 (16.77) | 301 (11.29) | ||
| Tobacco smoking | 81.419 | < 0.001 | ||
| No | 482 (51.83) | 1822 (68.32) | ||
| Yes | 448 (48.17) | 845 (31.68) | ||
| Alcohol consumption | 74.460 | < 0.001 | ||
| No | 603 (64.84) | 2107 (79.00) | ||
| Yes | 327 (35.16) | 560 (21.00) | ||
| Denture wearing | 34.302 | < 0.001 | ||
| No | 481 (51.72) | 1671 (62.65) | ||
| Yes | 449 (48.28) | 996 (37.35) | ||
| Recurrent oral ulceration | 100.673 | < 0.001 | ||
| No | 836 (89.89) | 2605 (97.68) | ||
| Yes | 94 (10.11) | 62 (2.32) |