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Table 2 Predictors of positive THC test among adolescent drivers: Unadjusted and adjusted odds ratiosa

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

  Unadjusted OR (95% CI) Multivariable Adjusted ORb (95% CI)
Model 1c Model 2d Model 3e
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)
  1. aTHC levels in oral fluid test or blood test, National Roadside Survey (NRS), 2013–2014
  2. 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
  3. cModel 1 included age, gender, household income and time since self-reported marijuana use
  4. 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
  5. 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)