Table 5

Effects of individual factors on the injury incidence risk after controlling for the effects of all other factors in the model: multivariate results

FactorN*IRR95%CIp Value
Intrinsic factors
 Age group0.01
  16–1710881.68(1.22 to 2.30)
  18–206831.10(0.66 to 1.83)
  21–246061.65(0.97 to 2.80)
  25–349511.52(0.91 to 2.54)
  35+4381.31(0.68 to 2.50)
  Pacific Island3901.48(1.03 to 2.13)
  Other42581.03(0.81 to 1.31)
 Strenuous physical activity (hours per week)0.01
  40+3641.54(1.11 to 2.15)
 Playing while injured<0.01
  Yes28891.46(1.20 to 1.79)
Extrinsic factors
 Grade played0.11
  Under 14/15/16/17/schoolboy27661.10(0.74 to 1.65)
  Under 18/195301.00
  Colts3340.93(0.50 to 1.72)
  Senior B/reserve6871.08(0.62 to 1.87)
  Senior A10501.49(0.89 to 2.49)
  Presidents/social3951.92(1.00 to 3.68)
  Other2681.07(0.57 to 2.01)
 Ground condition0.01
  Muddy22691.18(0.99 to 1.42)
  Very hard4491.50(1.13 to 2.00)
 Foul play<0.01
  Yes8781.87(1.54 to 2.27)
 Use of headgear0.05
  Not used42231.00
  Used18071.23(1.00 to 1.50)
  • * Number of player games (cases excluded if information missing from any of the factors in this model, therefore numbers can be smaller to those in univariate tables).

  • p Value for the overall significance of the factor.

  • IR, incidence rate; IRR, injury rate ratio.