Table 3.

Multivariate cox regressions for factors associated with initiation of injection drug use among female and male street-involved youth in Vancouver, Canada, September 2005–November 2011 (N = 422).

Characteristic	Adjusted HRa (95% CIb)	p Value
Model I: Male gender
Homelessd (yes vs. no)	1.73 (0.98–3.06)	0.058
Sex workd (yes vs. no)	4.74 (1.45–15.5)	0.010
Downtown Eastside residencyd (yes vs. no)	1.95 (1.12–3.41)	0.018
Model II: Female gender
Homelessd (yes vs. no)	1.79 (0.76–4.21)	0.185
Non-injection crystal meth usec,d (yes vs. no)	4.63 (1.89–11.35)	0.001
Crack cocaine smokingc,d (yes vs. no)	1.79 (0.73–4.41)	0.202
Non-injection heroine usec,d (yes vs. no)	1.66 (0.62–4.44)	0.309

^aHR, Hazard Ratio

^bCI, Confidence Interval

^cLagged to previous follow-up

^dDenotes behavior in the preceding 6 months