Table 4 Modified Poisson regression modeling of injecting and other risk factors for HCV infection among PWID in Dar es Salaam, Tanzania

Age at first injection

≤ 15

1

1

16–18

0.90 (0.46; 1.78)

0.86 (0.44; 1.69)

> 18

0.69 (0.40; 1.21)

0.61 (0.35; 1.07)

Duration of injection (years)

< 1

1

1

1–3

1.92 (0.57; 6.43)

1.99 (0.59; 6.70)

4–6

1.76 (0.52; 5.89)

1.81 (0.54; 6.10)

7–9

3.34 (1.03; 10.87)

3.41 (1.04; 11.14)

10+

3.06 (1.00; 9.41)

2.96 (1.00; 9.13)

Injection past month, how often

Once/day

1

1

> 1 per day

3.20 (0.90; 21.83)

3.25 (1.01; 22.41)

Once/week

2.71 (1.00; 20.64)

2.75 (0.93; 21.04)

> 1 per week

2.57 (0.84; 18.87)

2.65 (0.80; 19.65)

Access to clean needle

Yes

1

1

No

1.83 (1.54; 11.27)

1.76 (1.44; 12.74)

Flash blood past month*

No

1

1

Yes

2.19 (0.57; 8.44)

2.13 (0.55; 8.13)

Ever shared needle

Yes

1

1

No

0.94 (0.64; 1.36)

0.90 (0.63; 1.38)

Shared needle past month

No

1

1

Yes

1.68 (1.00; 2.94)

1.72 (1.02; 3.00)

Cleaned last time shared

Yes

1

1

No

2.27 (1.01; 6.38)

2.29 (1.00; 6.37)

On opioid treatment

Yes

1

No

0.40 (0.25; 0.64)

0.39 (0.24; 0.63)

Ever sold sex

Yes

1

1

No

0.84 (0.55; 1.29)

0.83 (0.55 (1.26)

Sold sex past month

No

1

1

Yes

1.24 (0.80; 1.91)

1.25 (0.81 (1.93)

Condom use last paid sex

Yes

1

1

No

1.77 (0.92; 3.43)

1.87 (1.00; 3.61)

Ever beaten past year

Yes

1

1

No

1.07 (0.73; 1.59)

1.02 (0.69; 1.52)

Forced sex past year

No

1

1

Yes

1.50 (0.81; 2.78)

1.49 (0.80; 2.76)

Ever arrested past year

No

1

1

Yes

1.47 (1.02; 2.12)

1.41 (0.97; 2.05)

Comprehensive HIV knowledge

No

1

1

Yes

1.07 (0.72; 1.57)

1.07 (0.73; 1.56)

Risk perception

High

1

1

Moderate

1.23 (0.72; 2.11)

1.26 (0.73; 2.15)

No or low

0.97 (0.65; 1.49)

0.98 (0.65; 1.50)