Table 5.

Likelihood of Mono- versus Polydrug Abuse by Demographic Variables and Study Years (N = 69,891)

	Total Users		Monodrug Users		Polydrug Users
	N = 69,891		n = 35,875 (51.3%)		n = 34,016 (48.7%)		Odds Ratio
Variable	N	%	n	%	n	%	ORa	95% CI
Gender
Male	48,168	68.9	24,646	51.2	23,522	48.8	0.979c	0.948–1.011
Female	21,723	31.1	11,229	51.7	10,494	48.3	1.021c	0.989–1.055
Ethnicity
Caucasian	46,910	69.2	26,218	55.9	20,692	44.1	1.957b	1.893–2.023
African American	20,393	30.1	7,941	38.9	12,452	61.1	0.504b	0.487–0.521
Other	495	0.7	269	54.3	226	45.7	1.154ns	0.967–1.379
Age
<18	6,955	10.0	4,525	65.1	2,430	34.9	1.876b	1.782–1.976
18–24	10,701	15.3	5,111	47.8	5,590	52.2	0.845b	0.811–0.880
25–34	20,671	29.6	9,347	45.2	11,324	54.8	0.706b	0.683–0.730
35–44	21,893	31.3	10,833	49.5	11,060	50.5	0.898b	0.870–0.927
45–54	8,266	11.8	4,931	59.7	3,335	40.3	1.466b	1.399–1.536
≥ 55	1,404	2.0	1,127	80.3	277	19.7	3.950b	3.461–4.509
Residential Area
Urban	35,062	50.2	17,035	48.6	18,027	51.4	0.802b	0.779–0.826
Rural	34,829	49.8	18,840	54.1	15,989	45.9	1.248b	1.210–1.285
Year
1998	9,911	14.2	4,645	46.9	5,266	53.1	0.812b	0.778–0.847
1999	9,123	13.1	4,327	47.4	4,796	52.6	0.836b	0.800–0.873
2000	9,598	13.7	5,293	55.1	4,305	44.9	1.194b	1.144–1.247
2001	10,214	14.6	5,618	55.0	4,596	45.0	1.189b	1.139–1.240
2002	9,891	14.2	4,885	49.4	5,006	50.6	0.913b	0.875–0.953
2003	10,738	15.4	5,711	53.2	5,027	46.8	1.092b	1.048–1.138
2004	10,416	14.9	5,396	51.8	5,020	48.2	1.023ns	0.981–1.066

^aOdds ratio of being a mono- versus a polydrug user in comparing a specific level of client demographics to all other demographic features. Odds in this table are calculated for the odds of being a mono vs. polydrug abuser, not for being male rather than female.

^bp < 0.0001.

^cp < 0.10.

^nsNot significant.