Table 1.
Demographic characteristics of the study participants in the training and validation datasets.
| Variable | Training dataset | Validation dataset | ||||
|---|---|---|---|---|---|---|
| Cases (%) | Controls (%) | P valuea | Cases (%) | Controls (%) | P valuea | |
| Age | ||||||
| Mean (SD) | 48.38 (11.07) | 49.22 (10.64) | 2.15E−01 | 49.30 (10.83) | 50.98 (10.91) | 1.07E−02 |
| < 28 | 16 (3.44) | 13 (2.21) | 4.23E−01 | 7 (1.64) | 10 (1.33) | 1.06E−02 |
| 28–59 | 377 (81.08) | 477 (80.98) | 347 (81.26) | 556 (74.03) | ||
| > 59 | 72 (15.48) | 99 (16.81) | 73 (17.10) | 185 (24.63) | ||
| Sex | ||||||
| Men | 349 (75.05) | 453 (76.91) | 5.29E−01 | 330 (77.28) | 581 (77.36) | 1.00E+00 |
| Women | 116 (24.95) | 136 (23.09) | 97 (22.72) | 170 (22.64) | ||
| Smoking | ||||||
| Never | 174 (37.42) | 217 (36.84) | 7.59E−01 | 182 (42.62) | 335 (44.61) | 3.79E−01 |
| Formerb | 34 (7.31) | 37 (6.28) | 27 (6.32) | 34 (4.53) | ||
| Current | 257 (55.27) | 335 (56.88) | 218 (51.05) | 382 (50.87) | ||
| Salted fish | ||||||
| Yearly or less | 314 (67.53) | 381 (64.69) | 5.84E−02 | 373 (87.35) | 612 (81.49) | 1.62E−02 |
| Monthly | 102 (21.94) | 162 (27.50) | 48 (11.24) | 113 (15.05) | ||
| weekly or more | 49 (10.54) | 46 (7.81) | 6 (1.41) | 26 (3.46) | ||
| Education | ||||||
| Illiterate or primary school | 183 (39.35) | 205 (34.80) | 2.55E−01 | 183 (42.86) | 284 (37.82) | 2.22E−01 |
| Middle school | 192 (41.29) | 244 (41.43) | 156 (36.53) | 292 (38.88) | ||
| High school | 70 (15.05) | 113 (19.19) | 73 (17.10) | 134 (17.84) | ||
| College or higher | 20 (4.30) | 27 (4.58) | 15 (3.51) | 41 (5.46) | ||
| Family history | ||||||
| No | 406 (87.31) | 568 (96.43) | 5.46E−08 | 389 (91.10) | 732 (97.47) | 1.97E−06 |
| Yes | 59 (12.69) | 21 (3.57) | 38 (8.90) | 19 (2.53) | ||
a The P value was calculated using a two-sided t-test. Other P values for categorical variables were calculated using χ2 tests.
b Individuals who had quit smoking more than 1 year before the interview were defined as former smokers.