Table 3.

Predictors of incident HCV infection stratified by sex*

	All participants		Females (n=140)		Males (n=277)
	HR	p Value	HR	p Value	HR	p Value
Female	1.43 (1.03 to 2.00)	0.03
Age	0.92 (0.88 to 0.96)	<0.01	0.93 (0.86 to 1.01)	0.07	0.93 (0.88 to 0.98)	0.01
Non-white race	0.91 (0.61 to 1.34)	0.62	1.19 (0.64 to 2.23)	0.59	0.77 (0.47 to 1.27)	0.31
Age of first injection	0.96 (0.93 to 1.00)	0.048	0.96 (0.90 to 1.03)	0.29	0.97 (0.92 to 1.02)	0.17
Years injecting	1.00 (0.96 to 1.05)	0.84	1.02 (0.95 to 1.09)	0.69	1.01 (0.96 to 1.07)	0.67
Injected every day	2.58 (1.84 to 3.62)	<0.01	2.06 (1.17 to 3.66)	0.01	2.86 (1.87 to 4.38)	<0.01
Injected heroin	2.71 (1.79 to 4.11)	<0.01	2.34 (1.14 to 4.83)	0.02	2.87 (1.73 to 4.75)	<0.01
Injected speed	1.48 (1.05 to 2.08)	0.03	1.12 (0.65 to 1.92)	0.68	1.80 (1.13 to 2.84)	0.01
Injected cocaine	2.32 (1.65 to 3.26)	<0.01	2.27 (1.34 to 3.83)	<0.01	2.49 (1.59 to 3.91)	<0.01
Reused a syringe	1.68 (1.11 to 2.54)	0.01	1.65 (0.85 to 3.19)	0.14	1.71 (1.1 to 2.91)	0.05
Reused a cooker	2.38 (1.70 to 3.33)	<0.01	1.96 (1.13 to 3.43)	0.02	2.47 (1.61 to 3.79)	<0.01
Used a syringe previously used by another injector	2.64 (1.88 to 3.70)	<0.01	2.71 (1.56 to 4.71)	<0.01	2.47 (1.61 to 3.79)	<0.01
Used a cooker previously used by another injector	2.38 (1.67 to 3.40)	<0.01	2.16 (1.31 to 3.59)	<0.01	2.26 (1.37 to 3.72)	<0.01
Did a rinse	2.66 (1.92 to 3.70)	<0.01	1.93 (1.13 to 3.28)	0.02	3.22 (2.16 to 4.81)	<0.01
Number of borrowing partners
1 (vs 0)	2.74 (1.84 to 4.09)	<0.01	3.31 (1.88 to 5.82)	<0.01	2.22 (1.26 to 3.91)	<0.01
>1 (vs 0)	2.54 (1.59 to 4.06)	<0.01	1.78 (0.73 to 4.35)	0.2	2.93 (1.74 to 4.95)	<0.01
Frequency of Injecting alone
Sometimes (vs never)	2.20 (1.48 to 3.26)	<0.01	1.84 (1.03 to 3.29)	0.04	2.54 (1.48 to 4.36)	<0.01
Always (vs never)	0.96 (0.50 to 1.83)	0.9	1.12 (0.34 to 3.70)	0.85	1.11 (0.50 to 2.45)	0.79
Frequency of pooling
Sometimes (vs never)	2.53 (1.70 to 3.76)	<0.01	1.61 (0.78 to 3.33)	0.2	2.93 (1.83 to 4.68)	<0.01
Always (vs never)	2.33 (1.40 to 3.87)	<0.01	2.29 (1.04 to 5.02)	0.04	1.56 (0.68 to 3.61)	0.3
Number of pooling partners
1 (vs 0)	2.62 (1.66 to 4.14)	<0.01	1.94 (0.88 to 4.27)	0.1	2.91 (1.65 to 5.12)	<0.01
>1 (vs 0)	2.50 (1.65 to 3.78)	<0.01	1.84 (0.87 to 3.87)	0.11	2.61 (1.58 to 4.34)	<0.01
Had a steady sex partner	1.73 (1.22 to 2.46)	<0.01	1.73 (0.88 to 3.39)	0.11	1.52 (0.96 to 2.38)	0.07
Had a steady sex partner who was also an IDU	2.23 (1.58 to 3.14)	<0.01	2.55 (1.32 to 4.94)	<0.01	1.88 (1.20 to 2.95)	<0.01

*Although interactions between primary predictor variables and female sex were also modelled, none reached significance at p<0.20.

HCV, hepatitis C virus; IDU, injection drug user.