Table 4

Unadjusted and adjusted odds of ATV fatalities comparing helmet versus no helmet and with head injury versus no head injury; CPSC, 1995–2009, (n=9615 fatalities)

	Helmet use*		Head injury†
	OR (95% CI)	aOR (95% CI)	OR (95% CI)	aOR (95% CI)
Rider characteristics
Sex
Male	1.17 (0.95 to 1.43)	1.22 (0.98 to 1.52)	0.93 (0.81 to 1.08)	0.98 (0.83 to 1.15)
Female	1.0 (ref)	1.0 (ref)	1.0 (ref)	1.0 (ref)
Age
<16	1.79 (1.57 to 2.05)	1.76 (1.51 to 2.07)	1.21 (1.10 to 1.33)	1.28 (1.12 to 1.45)
≥16	1.0 (ref)	1.0 (ref)	1.0 (ref)	1.0 (ref)
Seating position
Operator alone	1.0 (ref)	1.0 (ref)	1.0 (ref)	1.0 (ref)
Operator w/passenger	0.44 (0.36 to 0.55)	0.41 (0.33 to 0.51)	1.27 (1.11 to 1.45)	1.04 (0.90 to 1.20)
Passenger	0.52 (0.41 to 0.65)	0.42 (0.33 to 0.54)	1.66 (1.44 to 1.92)	1.41 (1.19 to 1.67)
Helmet
Yes	NA		0.52 (0.46 to 0.59)	0.54 (0.47 to 0.62)
No			1.0 (ref)	1.0 (ref)
Alcohol
Yes	0.70 (0.60 to 0.81)	0.55 (0.46 to 0.67)	1.20 (1.07 to 1.34)	1.16 (1.01 to 1.33)
No	1.0 (ref)	1.0 (ref)	1.0 (ref)	1.0 (ref)
Drugs
Yes-medication	0.47 (0.24 to 0.90)	0.47 (0.24 to 0.94)	0.60 (0.40 to 0.91)	0.65 (0.41 to 1.01)
Yes-illicit	0.66 (0.47 to 0.93)	0.99 (0.68 to 1.42)	1.28 (0.99 to 1.65)	1.19 (0.91 to 1.56)
No	1.0 (ref)	1.0 (ref)	1.0 (ref)	1.0 (ref)
Helmeted victim
On-road	NA		1.46 (1.13 to 1.88)	1.33 (1.00 to 1.76)
Off-road			1.0 (ref)	1.0 (ref)
Mechanism of crash
ATV-vehicle collision	NA		1.62 (1.44 to 1.82)	1.08 (0.93 to 1.27)
ATV-other collision			1.35 (1.22 to 1.49)	1.01 (0.89 to 1.15)
Non-collision			1.0 (ref)	1.0 (ref)
Location
Roadway	NA		1.89 (1.74 to 2.06)	1.45 (1.30 to 1.62)
Off-road			1.0 (ref)	1.0 (ref)

*Referent is not using a helmet.
†Referent is without head injury.
ATV, All-terrain vehicle; NA, not applicable.