| Risk factor | Mean medical costper injury† (95% CI) ($) | Wald p value | Mean human capital costper injury† (95% CI) ($) | Wald p value | Mean comprehensive costper injury† (95% CI) ($) | Wald p value |
| Intrinsic risk factors | ||||||
| Injury history | ||||||
| No | 476 (445 to 510) | Referent | 1553 (1447 to 1666) | Referent | 7719 (7208 to 8265) | Referent |
| Yes | 501 (470 to 534) | 0.33 | 1669 (1558 to 1788) | 0.20 | 8336 (7875 to 8821) | 0.13 |
| Years of playing experience | ||||||
| 0–1 year | 448 (395 to 508) | Referent | 1484 (1283 to 1716) | Referent | 7192 (6294 to 8217) | Referent |
| 2–4 years | 500 (469 to 534) | 0.13 | 1675 (1573 to 1783) | 0.15 | 8358 (7920 to 8821) | 0.05 |
| 5–8 years | 498 (460 to 538) | 0.14 | 1628 (1475 to 1796) | 0.26 | 8160 (7499 to 8879) | 0.11 |
| Age | ||||||
| ⩽16 years | 532 (471 to 600) | Referent | 1752 (1544 to 1988) | Referent | 8711 (7842 to 9676) | Referent |
| ⩾17 years | 473 (442 to 506) | 0.17 | 1570 (1471 to 1671) | 0.19 | 7843 (7391 to 8323) | 0.15 |
| BMI‡ | ||||||
| Under weight | 509 (349 to 744) | 0.85 | 1536 (1222 to 1931) | 0.54 | 8042 (6189 to 10449) | 0.87 |
| Normal weight | 499 (467 to 534) | Referent | 1645 (1530 to 1768) | Referent | 8209 (7737 to 8710) | Referent |
| Risk of overweight | 486 (437 to 540) | 0.71 | 1561 (1393 to 1748) | 0.52 | 7764 (6923 to 8707) | 0.46 |
| Overweight | 480 (435 to 528) | 0.46 | 1682 (1473 to 1922) | 0.78 | 8354 (7437 to 9384) | 0.79 |
| Play >1 sport | ||||||
| No | 543 (470 to 629) | Referent | 1779 (1502 to 2108) | Referent | 8657 (7528 to 9955) | Referent |
| Yes | 486 (465 to 508) | 0.14 | 1611 (1542 to 1684) | 0.25 | 8071 (7779 to 8374) | 0.33 |
| Extrinsic risk factors | ||||||
| Grade | ||||||
| 9-10 | 509 (459 to 565) | Referent | 1696 (1515 to 1899) | Referent | 8385 (7559 to 9301) | Referent |
| 11-12 | 489 (463 to 516) | 0.51 | 1614 (1526 to 1707) | 0.47 | 8075 (7684 to 8485) | 0.56 |
| Sport | ||||||
| Football | 577 (528 to 631) | Referent | 1831 (1656 to 2024) | Referent | 9311 (8567 to 10 120) | Referent |
| Boys’ soccer | 443 (388 to 507) | <0.01 | 1501 (1283 to 1756) | 0.06 | 7678 (6725 to 8766) | 0.03 |
| Girls’ soccer | 463 (408 to 527) | 0.01 | 1670 (1476 to 1888) | 0.29 | 7196 (6201 to 8350) | <0.01 |
| Boys’ track | 452 (334 to 611) | 0.13 | 1641 (1308 to 2060) | 0.51 | 8620 (6435 to 11 545) | 0.60 |
| Girls’ track | 377 (320 to 445) | <0.01 | 1619 (1381 to 1897) | 0.22 | 7637 (6674 to 8740) | 0.02 |
| Boys’ basketball | 401 (348 to 463) | <0.01 | 1337 (1184 to 1509) | <0.01 | 7011 (6353 to 7738) | <0.01 |
| Girls’ basketball | 354 (324 to 386) | <0.01 | 1257 (1124 to 1406) | <0.01 | 6162 (5584 to 6799) | <0.01 |
| Baseball | 466 (396 to 550) | 0.03 | 1454 (1249 to 1692) | 0.02 | 7385 (6433 to 8478) | 0.01 |
| Softball | 416 (347 to 499) | <0.01 | 1343 (1095 to 1647) | 0.01 | 5549 (4461 to 6901) | <0.01 |
| Wrestling | 670 (573 to 784) | 0.08 | 2080 (1782 to 2428) | 0.14 | 10212 (8607 to 12 115) | 0.34 |
| Volleyball | 322 (285 to 362) | <0.01 | 1181 (1058 to 1317) | <0.01 | 5918 (5335 to 6564) | <0.01 |
| Cheerleading | 465 (389 to 555) | 0.05 | 1640 (1341 to 2007) | 0.37 | 7366 (6142 to 8833) | 0.04 |
| Coach EQT | ||||||
| Low | 520 (473 to 572) | Referent | 1781 (1632 to 1945) | Referent | 8684 (8027 to 9394) | Referent |
| Medium | 474 (444 to 505) | 0.11 | 1529 (1428 to 1637) | 0.01 | 7694 (7248 to 8168) | 0.02 |
| High | 497 (461 to 537) | 0.46 | 1651 (1542 to 1767) | 0.24 | 8275 (7677 to 8920) | 0.38 |
| Competition division¶ | ||||||
| 1A | 545 (477 to 623) | Referent | 1815 (1672 to 1969) | Referent | 8920 (7916 to 10 050) | Referent |
| 2A | 539 (490 to 592) | 0.89 | 1783 (1570 to 2026) | 0.83 | 8866 (8054 to 9760) | 0.94 |
| 3A | 450 (414 to 488) | 0.02 | 1475 (1360 to 1600) | <0.01 | 7427 (6902 to 7992) | 0.01 |
| 4A | 470 (434 to 509) | 0.07 | 1565 (1444 to 1697) | 0.01 | 7817 (7293 to 8379) | 0.07 |
BMI, body mass index; coach EQT, coaching experience, qualifications, and training.
*Cost data were estimated for 2398 of 2990 reported injuries.
†Mean medical, human capital, and comprehensive costs are adjusted for prior injury, study year, sport, grade, multiple sports participation, coach EQT, years of playing experience, age, BMI, and competition division.
‡Underweight, ⩽5th centile; normal weight, >5th centile to <85th centile; at risk of overweight, ⩾85th centile to <95th centile; overweight, ⩾95th centile.
¶Division 1A, <668 students; division 2A, 668–957 students; division 3A, 967–1308 students; division 4A, 1314–2600 students.