Table 4

Prevalence and association between intervention and controls for substance use at subsequent waves presenting both unadjusted ORs (95% CI) and ORs (96% CI) adjusted for the appropriate variable at baseline (wave 1) and sociodemographic measures

	Number	Controls %	Intervention %	OR	95% CI	Adj*OR	95% CI
*Adjusted for measure at baseline (wave 1) and gender, family structure, Australian born, parental smoking.
Alcohol
Any drinking
Wave2	1081	44.0	39.4	0.83	(0.63 to 1.09)	0.93	(0.71 to 1.21)
Wave3	1227	53.6	50.3	0.88	(0.65 to 1.19)	1.00	(0.78 to 1.28)
Wave4	1619	70.2	66.3	0.83	(0.55 to 1.28)	0.96	(0.69 to 1.33)
Regular drinker
Wave2	253	10.0	9.4	0.93	(0.59 to 1.47)	1.09	(0.77 to 1.57)
Wave3	192	8.1	7.5	0.92	(0.56 to 1.49)	1.05	(0.70 to 1.57)
Wave4	106	4.4	4.5	1.02	(0.62 to 1.68)	1.13	(0.77 to 1.66)
Binge drinking
Wave2	478	19.3	17.4	0.88	(0.63 to 1.23)	0.95	(0.69 to 1.32)
Wave3	582	24.4	22.7	0.91	(0.64 to 1.30)	0.99	(0.70 to 1.38)
Wave4	815	34.6	33.3	0.94	(0.63 to 1.39)	1.02	(0.71 to 1.46)
Tobacco
Any smoking
Wave2	607	24.9	22.0	0.85	(0.66 to 1.09)	0.89	(0.72 to 1.12)
Wave3	638	28.7	25.0	0.83	(0.60 to 1.13)	0.92	(0.63 to 1.33)
Wave4	630	28.2	24.9	0.84	(0.64 1.11)	0.91	(0.67 to 1.24)
Regular smoker
Wave2	171	8.3	4.9	0.57	(0.36 to 0.91)	0.66	(0.46 to 0.95)
Wave3	232	11.9	7.7	0.62	(0.39 to 0.99)	0.72	(0.47 to 1.09)
Wave4	322	15.6	11.8	0.72	(0.52 to 1.00)	0.79	(0.58 to 1.07)
Marijuana use
Any in past 6 months
Wave2	307	12.2	11.5	0.94	(0.62 to 1.41)	0.98	(0.69 to 1.40)
Wave3	219	9.6	10.0	1.04	(0.72 to 1.50)	1.06	(0.75 to 1.49)
Wave4	466	21.7	18.6	0.83	(0.58 to 1.17)	0.81	(0.57 to 1.16)
Friends’ use
Alcohol
Wave2	1468	58.5	54.6	0.85	(0.59 to 1.23)	0.96	(0.67 to 1.37)
Wave3	1663	71.3	66.8	0.81	(0.56 to 1.17)	0.91	(0.64 to 1.27)
Wave4	2027	88.5	82.9	0.63	(0.40 to 1.00)	0.71	(0.47 to 1.09)
Tobacco
Wave2	371	15.9	12.7	0.77	(0.48 to 1.23)	0.79	(0.51 to 1.21)
Wave3	433	19.8	16.0	0.77	(0.51 to 1.18)	0.84	(0.52 to 1.36)
Wave4	530	24.2	20.6	0.81	(0.57 to 1.16)	0.87	(0.60 to 1.26)