Gender differences in mortality and risk factors in a 13-year cohort study of street-recruited injecting drug users

Table 3 Adjusted effects of substitution treatment, incarceration and prison release on risk of mortality assessed using Cox regression analysis in a limited study period 1.1.1998 and 31.12.2004 (n = 169) ^ab

	Model 1: total population	Model 2: total population	Model 3: women	Model 4: men
	Adjusted HR^b[95% CI]	Adjusted HR^b[95% CI]	Adjusted HR^b[95% CI]	Adjusted HR^b[95% CI]
Male	-	1.7 [0.7, 4.3]	-	-
≥ 30 years^c	-	0.8 [0.3, 1.9]	1.5 [0.2, 12.1]	0.5 [0.2, 1.3]
> 5 years IV career^{c, d}	-	1.5 [0.5, 4.2]	0.7 [0.0, 13.8]	1.7 [0.5, 5.2]
Heroin and prescription drugs^{e, f}	-	1.4 [0.7, 3.0]	0.8 [0.1, 4.1]	1.5 [0.6, 3.5]
Alcohol ≥2 days a week^f	-	1.1 [0.5, 2.3]	2.6 [0.3, 20.8]	1.1 [0.5, 2.5]
Sex work^f	-	-	22.7 [1.5, 333.8]**	-
Total years in OST	0.7 [0.5, 0.9]**	0.7 [0.5, 0.9]**	0.1 [0.0, 0.6]**	0.7 [0.5, 1.0]**
Total years in prison	0.1 [0.0, 0.6]***	0.1 [0.0, 0.6]***	0.0 [0.0, 0.7]**	0.1 [0.0, 0.6]**
Prison release^a	4.3 [0.5, 34.7]	3.7 [0.4, 30.3]	-^g	3.2 [0.6, 16.4]

*p < 0.10, **p < 0.05, ***p < 0.001.
^aData was only available from OST from 1.1.1998 when OST was established as a national programme in Norway. The follow-up time for this table is therefore from 1.1.1998-31.12.2004. Three cases died before 1.1.1998 and therefore had to be omitted; the study population was therefore 169 and not 172 as in the original sample.
^bIt was not possible to run the log logistic regression model due data organization. Please see the Methods section for more detail. However, this model satisfied the proportionality assumption and therefore a Cox regression survival analysis could be used. In this model HR and 95% CI are reported.
^cAt inclusion.
^d> 5 years between first injection and interview.
^eCombined heroin and prescription drugs in injections.
^fIn the previous four weeks before the baseline interview.
^gUnable to estimate the effect of prison release on women due to a small sample size.

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