Table 2

OR estimates of substance use before injury with every control period and total, by type of substance and measurement

First control periodSecond control periodMultiple matching
obsOR95% CI obsOR95% CI obsOR95% CI
Self-report6645.62*(2.65 to 11.93)6065.71*(2.56 to 12.76)9675.49*(3.06 to 9.84)
Alcosensor (BAC≥0.001)5163.67*(1.75 to 7.66)4703.22*(1.53 to 6.81)7513.70*(2.04 to 6.72)
Self-report or alcosensor6646.25*(2.96 to 13.18)6066.43*(2.90 to 14.25)9676.14*(3.45 to 10.93)
Alcosensor or SR if missing6643.55*(1.82 to 6.92)6063.00*(1.56 to 5.77)9673.43*(2.02 to 5.83)
Self-report6581.30(0.57 to 2.96)6040.80(0.32 to 2.03)9621.12(0.50 to 2.47)
Oral fluid4840.67(0.27 to 1.63)4480.77(0.34 to 1.75)7100.69(0.31 to 1.57)
Self-report or oral fluid6582.22*(1.01 to 4.88)6041.89(0.84 to 4.24)9622.40*(1.18 to 4.88)
Oral fluid or SR if missing6580.86(0.40 to 1.85)6040.75(0.35 to 1.59)9620.83(0.41 to 1.67)
  • ORs were estimated using conditional logistic regression.

  • *P<0.05.

  • obs are the number of case and control periods used in each model (ie, each person contributed with a maximum of three observed case and control periods for the multiple matching models).

  • BAC, breath alcohol concentration; SR, self-report.