Select characteristics of the US Air Force study population
| Characteristic | TGCT cases (N=530) | Controls (N=530) |
| N (%) | N (%) | |
| Age at serum sample collection (year) | ||
| <20 | 141 (26.6) | 134 (25.3) |
| 20–24 | 194 (36.6) | 220 (41.5) |
| 25–29 | 95 (17.9) | 76 (14.3) |
| 30–34 | 64 (12.1) | 66 (12.4) |
| 35–39 | 28 (5.3) | 27 (5.1) |
| 40+ | 8 (1.5) | 7 (1.3) |
| Age at TGCT diagnosis (year) | ||
| <20 | 10 (1.9) | |
| 20–24 | 111 (20.9) | |
| 25–29 | 159 (30) | |
| 30–34 | 113 (21.3) | |
| 35–39 | 89 (16.8) | – |
| 40+ | 48 (9.1) | – |
| Mean±SD | 29.8±6.6 | – |
| Race/ethnicity at case diagnosis | ||
| Non-Hispanic white | 422 (79.6) | 422 (79.6) |
| Non-Hispanic black | 13 (2.4) | 13 (2.4) |
| Hispanic | 57 (10.8) | 57 (10.8) |
| Asian/Pacific Islander | 6 (1.1) | 6 (1.1) |
| Native American/Alaska Native | 5 (0.9) | 5 (0.9) |
| Other | 9 (1.7) | 9 (1.7) |
| Unknown | 18 (3.4) | 18 (3.4) |
| Education at case diagnosis | ||
| ≤High school | 261 (49.3) | 268 (50.6) |
| Some college | 120 (22.6) | 138 (26) |
| Bachelor's | 80 (15.1) | 57 (10.8) |
| Advanced degree | 68 (12.8) | 66 (12.4) |
| Unknown | 1 (0.2) | 1 (0.2) |
| Grade at case diagnosis | ||
| Enlisted (E01–E10) | 410 (77.4) | 435 (82.1) |
| Officer (O1–O10) | 120 (22.6) | 95 (17.9) |
| Height (m) at military accession | ||
| Mean±SD | 1.65±0.24 | 1.61±0.21 |
| % Missing | 190 (35.8) | 181 (34.2) |
| Weight (kg) at military accession | ||
| Mean±SD | 69.9±2.59 | 69.5±2.48 |
| % Missing | 190 (35.8) | 181 (34.2) |
| Number of deployments before case dx year | ||
| 0 | 386 (72.8) | 354 (67.4) |
| 1 | 81 (15.3) | 92 (17.4) |
| 2 | 35 (6.6) | 50 (9.4) |
| ≥3 | 28 (5.3) | 32 (5.8) |
| Years of service at serum sample collection | ||
| Mean±SD | 2.4±3.3 | 2.4±3.3 |
| Years of service at case dx | ||
| Mean±SD | 8.2±5.3 | 8.2±5.2 |
| Time between serum collection and case dx (years) | ||
| Mean±SD | 5.8±4.4 | 5.8±4.4 |
| Calendar year of military accession | ||
| Median (range) | 1998 (1986–2017) | 1998 (1986–2017) |
| Calendar year of serum sample draw | ||
| Median (range) | 1999 (1988–2017) | 1999 (1989–2017) |
| Calendar year at case dx | ||
| Median (range) | 2007 (1990–2018) | 2007 (1990–2018) |
| Tumour morphology | ||
| Seminoma | 293 (55.3) | |
| Non-seminoma | 237 (44.7) |
Controls individually matched to cases on: race/ethnicity, military accession year (±1 year), date of birth (±1 year) and serum sample collection date (±1 year).
*Defined as a deployment record with a length of ≥31 days outside of the USA.
dx, diagnosis; TGCT, testicular germ cell tumour.