Marijuana use in U.S. teen drivers: a comparison of a road-side survey of reported use and fluid tests for tetrahydrocannabinol (THC)

Table 2 Predictors of positive THC test among adolescent drivers: Unadjusted and adjusted odds ratios^a

	Unadjusted OR (95% CI)	Multivariable Adjusted OR^b (95% CI)
	Unadjusted OR (95% CI)	Model 1^c	Model 2^d	Model 3^e
Demographic Characteristics
Age (yrs)
16–17	Ref	Ref	Ref	Ref
18–19	2.17 (1.12, 4.19)	1.34 (0.61, 2.97)	1.19 (0.57, 2.52)	1.21 (0.57, 2.57)
Gender
Female	Ref	Ref	Ref	Ref
Male	1.66 (1.02, 2.71)	1.81 (0.99, 3.32)	1.64 (0.93, 2.89)	1.58 (0.88, 2.80)
Household income
0 < $25,000	Ref	Ref	Ref	Ref
$25,001 < $50,000	0.71 (0.40, 1.27)	0.90 (0.45, 1.82)	0.90 (0.47, 1.74)	0.85 (0.44, 1.67)
$51,001 < $75,000	0.59 (0.30, 1.187)	0.79 (0.35, 1.81)	0.62 (0.28, 1.38)	0.55 (0.24, 1.25)
$75,001 and more	0.45 (0.24, 0.84)	0.42 (0.20, 0.92)	0.47 (0.24, 0.93)	0.46 (0.23, 0.92)
Substance use
Self-reported marijuana use
Beyond a year/Never	Ref	Ref
Over a month	3.45 (1.69, 7.02)	3.31 (1.48, 6.64)
Past month	2.93 (1.13, 7.60)	2.38 (0.84, 6.74)
Past 2 days	8.42 (3.11, 22.78)	8.28 (2.88, 23.81)
Past 24 h	38.51 (18.20, 81.46)	40.21 (18.02, 89.74)
Current Marijuana Use
Beyond a year/Never	Ref		Ref	Ref
Used in last year			5.60 (3.23, 9.73)	5.28 (3.01, 9.24)
Tobacco use
Beyond a year/Never	Ref		Ref	Ref
Current user	4.22 (2.56, 6.96)		1.81 (1.02, 3.23)	2.05 (1.13, 3.70)
Self-reported age at first alcohol use (yrs)
Does not drink/After 15	Ref		Ref	Ref
≤ 15	3.02 (1.70 5.38)		2.17 (1.12, 4.19)	2.27 (1.13, 3.70)
Time of year
June–August	Ref			Ref
September–March	2.84 (1.57, 5.16)			3.18 (1.60, 6.21)

^aTHC levels in oral fluid test or blood test, National Roadside Survey (NRS), 2013–2014
^bRace/ethnicity, census region, presence or absence of a medical marijuana law, and educational levels were tested in all models, but were dropped from all models due to lack of significance
^cModel 1 included age, gender, household income and time since self-reported marijuana use
^dModel 2 included age, gender, household income, marijuana use in last year (Y/N), tobacco use in last 24 h, and began drinking alcohol by age 16 years
^eModel 3 added time of year of survey/fluid testing to variables in model 2 (age, gender, household income, marijuana use in last year (Y/N), tobacco use in last 24 h, and began drinking alcohol by age 16 years)

ISSN: 2197-1714