Table 2.

Unadjusted odds ratios estimated from conditional logistic regression for SES in relation to newly incident drug use, with classroom-level matching. Data from Sao Paulo City private school survey, Brazil, 2008 (n=4476).

Newly Incident	(n^b)	Pr	SES	A1	A2	B1	B2	CDE

			n^a	464	1492	1439	833	248
Use of Lanca			OR	ref	0.8	0.5	0.4	0.2
	94	11.7%	95% CI		0.4, 1.7	0.2, 1.1	0.2, 0.9	0.1,0.8
			p		0.60	0.10	0.04	0.02

Use of Inhalant Drugs Other than Lanca			OR	ref	0.7	0.6	0.5	0.3
	62	14.5%	95% CI		0.4, 1.1	0.3, 0.9	0.3, 0.9	0.1, 0.7
			p		0.100	0.020	0.010	0.005

Drinking of Alcoholic Beverages			OR	ref	0.6	0.5	0.6	0.7
	1083	14.1%	95% CI		0.4, 0.9	0.3, 0.7	0.3, 0.9	0.4, 1.3
			P		0.010	0.001	0.010	0.400

Smoking of Tobacco			OR	ref	0.6	0.6	0.4	0.4
	466	16.1%	95% CI		0.4, 0.8	0.4, 0.8	0.3, 0.7	0.2, 0.8
			p		0.002	0.004	<0.001	0.008

Use of Internationally Regulated Drugs			OR	ref	0.4	0.3	0.3	No newly incident users
	332	19.9%	95% CI		0.2, 0.9	0.1, 0.7	0.1, 0.8
			p		0.020	0.005	0.010

IRD

SES = social rank according to ABEP classification

n^a = unweighted number of youths at each family SES rank.

OR = odds ratio estimate from conditional form of logistic regression, no other covariates in the model, where ‘ref’ indicates that the highest social rank served as the reference category for estimation of the odds ratios.

CI = confidence interval

p = p-value under the null hypothesis of no association between SES and drug use occurrence as studied here.

n^b = unweighted number of drug-using youths in the highest SES rank (A1).

Pr = estimated prevalence of recently active use of each drug listed in the highest SES (A1) rank.