Table III.

Logistic regression model for likelihood of CNS injury after off-road motorized vehicle crash

Variable	Odds ratio	95% Confidence interval	p
Helmet use	0.28	0.18–0.44	<0.001
Vehicle type
ATV	1.0	–	–
Snowmachine	0.60	0.39–0.93	0.02
Motorbike	0.75	0.44–1.29	0.30
Age (per year increase)	0.98	0.93–1.03	0.17
Male sex	0.96	0.65–1.41	0.84
Ethnicity
Alaska Native/American Indian	1.0	–	–
White/other	1.07	0.68–1.68	0.78
Community type
Urban	1.0	–	–
Large rural	1.10	0.52–2.34	0.81
Small, isolated rural	0.75	0.47–1.19	0.22
Recent alcohol use	0.94	0.48–1.83	0.85
Recent drug use	6.58	2.92–14.92	<0.001