Table 7

Results of Cox proportional hazard analysis

UnivariateMultivariate
CategoryCovariatesNExp (b)95% CIp ValueExp (b)95% CIp Value
Demographic/biometricAge
≤16.9 years42011
>16.9 years4001.441.15 to 1.820.0021.451.14 to 1.830.002
Weight
≤77 kg41911
>77 kg4011.441.14 to 1.810.0021.321.04 to 1.690.023
Height
≤1.78 m4421
>1.78 m3781.060.84 to 1.330.597
Playing position
Backs3851
Forwards4341.070.85 to 1.340.581
Injury historyAny previous injury
No2631
Yes5491.060.83 to 1.350.658
Previous concussion
No51411
Yes2951.301.02 to 1.670.0371.260.98 to 1.620.068
Use of protective equipmentMouthguard
No17111
Yes6380.720.55 to 0.930.0120.700.54 to 0.920.010
Shoulder pads
No5571
Yes2521.020.79 to 1.300.881
Helmet (soft)
No5491
Yes2581.070.84 to 1.370.571
Strength profileRegular weight training
No12411
Yes6841.871.26 to 2.760.0021.651.11 to 2.460.014
Upper body (1RM)
≤75 kg3241
>75 kg3781.080.85 to 1.400.511
Lower body (1RM)
≤110 kg3411
>110 kg3331.010.78 to 1.300.935
Level of playAge first started playing rugby
≤10 years3991
>10 years4061.130.90 to 1.420.305
School team ranking
Top tier25511
Middle tier2360.600.45 to 0.800.0000.670.49 to 0.900.009
Lower tier2970.650.50 to 0.840.0010.770.58 to 1.020.065
Involved in provincial rugby
No66711
Yes1441.831.40 to 2.370.0001.421.06 to 1.900.017
  • 1RM, 1 repetition maximum.