Age differences in heroin and prescription opioid abuse among enrolees into opioid treatment programs

Table 3 Multinomial logistic multilevel model predicting type of opioid use: Helmert contrasts of individual age

	*PO & Heroin vs. Heroin Only*				*PO Only vs. Heroin Only*
	Odds Ratio 95% Confidence Interval				Odds Ratio 95% Confidence Interval
	Lower	Estimate	Upper	p	Lower	Estimate	Upper	p
Individual Age Within Programs
20-25 vs. Younger	0.859	0.962	1.077	0.497	1.017	1.156	1.314	0.027
26-29 vs. Younger	0.873	0.915	0.959	<.001	0.930	0.980	1.033	0.446
30-39 vs. Younger	0.903	0.927	0.951	<.001	0.948	0.976	1.004	0.093
40-49 vs. Younger	0.913	0.931	0.948	<.001	0.944	0.964	0.986	0.001
50-59 vs. Younger	0.923	0.940	0.958	<.001	0.940	0.960	0.981	<.001
60-70 vs. Younger	0.888	0.926	0.965	<.001	0.927	0.973	1.021	0.269
Interview Year
2006 vs. 2005	0.869	0.959	1.058	0.403	1.042	1.167	1.307	0.007
2007 vs. 2005	0.978	1.091	1.217	0.119	1.164	1.317	1.489	<.001
2008 vs. 2005	1.864	2.071	2.300	<.001	1.962	2.215	2.500	<.001
2009 vs. 2005	1.933	2.146	2.382	<.001	2.134	2.404	2.708	<.001
Beale Urbanicity
Medium vs. High Density	1.883	2.130	2.410	<.001	2.783	3.155	3.578	<.001
Low vs. High Density	2.837	3.792	5.067	<.001	4.706	6.220	8.221	<.001
U.S. Region
Southeast vs. Northeast	2.093	2.468	2.911	<.001	15.955	18.867	22.310	<.001
Midwest vs. Northeast	3.092	3.750	4.548	<.001	9.259	11.281	13.745	<.001
West vs. Northeast	0.899	0.997	1.105	0.954	2.241	2.526	2.846	<.001

Note: OTP averages of age contrasts were included in the model but are not shown here because it is not clear how to interpret them and the primary purpose of including them in the model is partialling out OTP-level age differences so that individual patient age contrasts can be unambiguously interpreted as pooled within-OTP associations. All associations were tested for significance using z-tests, in which the coefficient was divided by its standard error and compared with the normal distribution. Coefficients and confidence limits were exponentiated to odds ratios for presentation here. Sample sizes for this analysis were 29107 individual enrolees nested within one of 85 OTPs.

ISSN: 1747-597X