Table 1.

Demographics in the RFAB and MTFS studies

CharacteristicRFABMTFS
Nonusers (n = 314)Users (n = 475)Significant, PNonusers (n = 1,455)Users (n = 822)Significant, P
Age at baseline, y9.6 ± 0.59.6 ± 0.611.8 ± 0.411.8 ± 0.4
Age at follow-up, y19.5 ± 1.120.0 ± 1.2<0.0518.0 ± 0.618.2 ± 0.7<0.05
Marijuana use >30 times, %49.337.0
Daily marijuana use, %20.822.6
Maximal binge drinking*2.7 ± 2.57.3 ± 2.1<0.052.6 ± 2.811.3 ± 2.2<0.05
Other drug use, %1.638.3<0.056.639.4<0.05
SES, percentile59.4 ± 30.256.2 ± 30.552.1 ± 21.148.6 ± 21.7<0.05
Male, %43.946.744.655.0<0.05
MZ, %51.140.7<0.0563.261.0
Race, %
 Caucasian26.832.6<0.0595.388.9<0.05
 African American12.411.4
 Hispanic34.737.5
 Asian7.61.5
 Multiracial18.517.1
  • * RFAB, n = 270 and 421. Maximal binge drinking was measured as the largest number of drinks consumed in a 24-h period.