Risk factor analyses for game-related injury, severe injury, concussion and concussion with more than 10 days of time loss in Pee Wee ice hockey in Alberta 2011–2012 and 2013–2014
| Incidence rate ratios (95% CI) | |||||||||
| Risk factor | All injury adjusted* | Severe injury† (>7 days of time loss) | Concussion adjusted‡ | Concussion† (>10 days of time loss) | |||||
| Cohort | |||||||||
| n=1501 | 2013–2014 | 0.50 | (0.33 to 0.75) | 0.40 | (0.24 to 0.68) | 0.36 | (0.22 to 0.58) | 0.56 | (0.31 to 1.01) |
| 2011–2012 | 1 (Reference) | 1 (Reference) | 1 (Reference) | 1 (Reference) | |||||
| Year of play | |||||||||
| n=1493 | First | 1.39 | (0.98 to 1.96) | 1.21 | (0.82 to 1.78) | 2.63 | (1.58 to 4.37) | 1.83 | (1.09 to 3.07) |
| Second | 1 (Reference) | 1 (Reference) | 1 (Reference) | 1 (Reference) | |||||
| Player size | |||||||||
| n=1294 | Low weight (≤36.4 kg) | 1.32 | (0.92 to 1.90) | 1.32 | (0.81 to 2.13) | 1.39 | (0.89 to 2.15) | 1.58 | (0.86 to 2.91) |
| High weight (>36.4 kg) | 1 (Reference) | 1 (Reference) | 1 (Reference) | 1 (Reference) | |||||
| Level of play | |||||||||
| n=1499 | Upper (div 1–3, top 30%) | 1.01 | (0.70 to 1.45) | 1.20 | (0.73 to 1.96) | 0.97 | (0.62 to 1.54) | 1.17 | (0.69 to 2.01) |
| Lower (div 4–12, lower 70%) | 1 (Reference) | 1 (Reference) | 1 (Reference) | 1 (Reference) | |||||
| Previous injury (including concussion in the last year) | |||||||||
| n=1469 | Yes | 1.70 | (1.13 to 2.58) | 1.92 | (1.24 to 2.96) | NA | NA | ||
| No | 1 (Reference) | 1 (Reference) | NA | NA | |||||
| Previous concussion (any concussion, no date limit) | |||||||||
| n=1494 | Yes | NA | NA | 2.48 | (1.64 to 3.76) | 2.66 | (1.60 to 4.44) | ||
| No | NA | NA | 1 (Reference) | 1 (Reference) | |||||
| Position | |||||||||
| n=1444 | Defence | 1.19 | (0.86 to 1.65) | 1.04 | (0.67 to 1.61) | 1.00 | (0.66 to 1.52) | 1.02 | (0.55 to 1.88) |
| Goalie | 0.16 | (0.04 to 0.65) | 0.36 | (0.12 to 1.06) | 0.23 | (0.05 to 1.04) | 0.18 | (0.02 to 1.35) | |
| Forward | 1 (Reference) | 1 (Reference) | 1 (Reference) | 1 (Reference) | |||||
| Attitudes toward body checking | |||||||||
| n=1372 | High (≥36/55) | 1.02 | (0.70 to 1.46) | 1.19 | (0.74 to 1.92) | 0.93 | (0.62 to 1.40) | 1.07 | (0.61 to 1.88) |
| Low (<36/55) | 1 (Reference) | 1 (Reference) | 1 (Reference) | 1 (Reference) | |||||
*Incidence rate ratios based on Poisson regression analysis offset for exposure hours and adjusted for clustering by team and covariates (cohort, year of play, previous injury or concussion in the last year, player size, level of play, position of play and attitudes toward body checking). Complete case analysis included 1134 participants.
†Incidence rate ratios based on Poisson regression analysis offset for exposure hours and adjusted only for clustering by team, owing to fewer injuries.
‡Incidence rate ratios based on Poisson regression analysis offset for exposure hours and adjusted for clustering by team and covariates (cohort, year of play, previous concussion, player size, level of play, position of play and attitudes toward body checking). Complete case analysis included 1145 participants.
div, division; NA, not applicable; n, number of cases included in univariate analysis.