Table 3 Multivariable Poisson regression modelling

	Unselected MVCs		MVCs with injury
	Rate ratio (95% CI)	p Value	Rate ratio (95% CI)	p Value
Patients
Presence of OSAH	1.22 (0.92 to 2.01)	0.12	3.67 (1.30 to 10.3)	0.014
ESS	1.01 (0.99 to 1.04)	0.35	1.04 (0.99 to 1.09)	0.11
Male sex	0.91 (0.66 to 1.25)	0.55	0.59 (0.32 to 1.09)	0.09
Age	1.00 (0.99 to 1.01)	0.69	0.99 (0.97 to 1.02)	0.50
BMI	1.01 (1.00 to 1.02)	0.008	0.99 (0.96 to 1.03)	0.69
Per 100 km driven/week	1.09 (1.03 to 1.16)	0.003	1.12 (1.00 to 1.25)	0.053
Alcohol use*	1.01 (1.00 to 1.03)	0.12	1.05 (1.02 to 1.07)	0.0014
Sedative use	0.79 (0.49 to 1.28)	0.34	0.96 (0.41 to 2.23)	0.92
Caffeine use†	0.99 (0.98 to 1.00)	0.15	0.99 (0.5 to 1.3)	0.19

Controls
Male sex	1.55 (1.00 to 2.41)	0.049	2.39 (0.71 to 8.08)	0.13
Age	0.99 (0.98 to 1.01)	0.38	0.95 (0.92 to 0.99)	0.006

BMI, body mass index; ESS, Epworth Sleepiness Scale; MVC, motor vehicle crash; OSAH, obstructive sleep apnoea/hypopnoea.
*For every one increase in alcohol use per week (ie, bottle/can/glass of beer, 4 oz wine or drink/shot of liquor).
†For every one cup increase in coffee use per week.