Table 1 Characteristics of the study population
Characteristic | Cases (N = 742) | Controls (N = 742) | P-value 1 | ||
|---|---|---|---|---|---|
N | (%) | N | (%) | ||
Age at serum sample collection (yr) | |||||
 17–19 | 123 | (16.6) | 121 | (16.3) |  |
 20–29 | 349 | (47.0) | 352 | (47.4) |  |
 30–39 | 220 | (29.7) | 221 | (29.8) |  |
 40–52 | 50 | (6.7) | 48 | (6.5) | 0.99 |
 Mean ± SD | 27.3 | ± 7.4 | 27.2 | ± 7.3 |  |
Age at PTC diagnosis (yr) a | |||||
 20–29 | 210 | (28.3) | 203 | (27.4) |  |
 30–39 | 310 | (41.8) | 323 | (43.5) |  |
 40–49 | 185 | (24.9) | 179 | (24.1) |  |
 50–62 | 37 | (5.0) | 37 | (5.0) | 0.92 |
 Mean ± SD | 35.1 | ± 8.1 | 35.1 | ± 8.0 |  |
Sex | |||||
 Female | 341 | (46.0) | 341 | (46.0) |  |
 Male | 401 | (54.0) | 401 | (54.0) | > 0.99 |
Race/ethnicity | |||||
 Non-Hispanic White | 468 | (63.1) | 467 | (62.9) |  |
 Non-Hispanic Black | 131 | (17.6) | 132 | (17.8) |  |
 Hispanic | 68 | (9.2) | 68 | (9.2) |  |
 Other | 55 | (7.4) | 55 | (7.4) |  |
 Unknown | 20 | (2.7) | 20 | (2.7) | > 0.99 |
BMI (kg/m2) | |||||
 16.3–24.9 | 257 | (34.6) | 285 | (38.4) |  |
 25-34.8 | 164 | (22.1) | 139 | (18.7) |  |
 missing | 321 | (43.3) | 318 | (42.9) | 0.17 |
Service branch | |||||
 Army | 299 | (40.3) | 253 | (34.1) |  |
 Air Force | 193 | (26.0) | 150 | (20.2) |  |
 Navy | 186 | (25.1) | 248 | (33.4) |  |
 Marines & Coast Guard | 64 | (8.6) | 91 | (12.3) | < 0.0001 |
Years from serum sample collection to PTC diagnosis b | |||||
 3–4 | 115 | (15.5) | 111 | (14.9) |  |
 5–9 | 345 | (46.5) | 350 | (47.2) |  |
 10–12 | 282 | (38.0) | 281 | (37.9) | 0.95 |
 Mean ± SD | 8.4 | ± 2.7 | 8.4 | ± 2.7 |  |
Tumor size (mm) | |||||
 ≤10 | 235 | (31.7) |  |  |  |
 >10 | 463 | (62.4) |  |  |  |
 Missing | 44 | (5.9) |  |  |  |
Histological type | |||||
 Classical PTC | 600 | (80.9) |  |  |  |
 Follicular variant of PTC | 142 | (19.1) |  |  |  |