Table 3.

Mortality and injury risks associated with helmet use

Patient characteristics	Helmet	No helmet	Univariate OR (95% CI)	Multivariate OR (95% CI)
	(n=1821)	(n=5338)
Intracranial injury	835 (45.9)	2999 (56.2)	0.66 (0.59 to 0.74)	0.69 (0.61 to 0.77)
Epidural hematoma	13 (0.7)	132 (2.5)	0.28 (0.16 to 0.50)	0.31 (0.17 to 0.56)
Subdural hematoma	155 (8.5)	792 (14.8)	0.53 (0.45 to 0.64)	0.50 (0.42 to 0.61)
Subarachnoid hematoma	231 (12.7)	836 (15.7)	0.78 (0.67 to 0.91)	0.76 (0.64 to 0.89)
Skull fracture	329 (18.1)	1680 (31.5)	0.48 (0.42 to 0.55)	0.51 (0.45 to 0.59)
Facial injury	271 (14.9)	1058 (19.8)	0.70 (0.61 to 0.82)	0.76 (0.66 to 0.89)
Cervical spine injury	254 (13.9)	478 (8.9)	1.65 (1.40 to 1.94)	1.69 (1.47 to 1.96)
Severe injury	794 (46.3)	2421 (48.6)	0.91 (0.82 to 1.02)	0.92 (0.82 to 1.03)
Mortality	88 (4.8)	441 (8.3)	0.56 (0.45 to 0.71)	0.53 (0.42 to 0.67)

Covariates in the multivariate logistic regression models included age >65, gender, insurance status, and intoxication. In the mortality analysis, we additionally included head injury and abdominal injury in the multivariate model.