Table 4

Cluster adjusted risk ratios and Cox proportional hazard ratios comparing the incidence of SRC between the HG and NoHG groups

nSRC% SRCMultivariate risk ratioMultivariate HR
95% CIP value95% CIP value
Intent to treat
 All no headgear1545684.4ReferenceReference
 All headgear1505624.10.98 (0.62 to 1.56)0.9460.98 (0.64 to 1.51)0.935
 Males—no headgear54681.5ReferenceReference
 Males—headgear474143.01.83 (0.60 to 5.53)0.2862.00 (0.63 to 6.43)0.242
 Females—no headgear999606.0ReferenceReference
 Females—headgear1031484.70.90 (0.55 to 1.48)0.6830.86 (0.54 to 1.36)0.520
As treated
 All no headgear1546754.9ReferenceReference
 All headgear1504553.70.63 (0.37 to 1.08)0.0910.78 (0.48 to 1.25)0.303
 Males—no headgear548101.8ReferenceReference
 Males—headgear472122.50.93 (0.27 to 3.20)0.9091.33 (0.43 to 4.11)0.623
 Females—no headgear998656.5ReferenceReference
 Females—headgear1032434.20.64 (0.38–1.08)0. 0940.70 (0.43 to 1.15)0.154
  • Multivariable analysis consisted of Poisson regression and Cox proportional hazards survival analysis controlling for age, sex, year, concussion in the last year and symptom severity group as covariates and school cluster effect.

  • As treated designation is based on majority headgear use (yes/no) for those without an SRC, and whether they were wearing headgear when SRC occurred for those with SRC.

  • HG, headgear group; NoHG, no headgear group; SRC, sport-related concussion.