Table 2.

Pooled estimates of young PWID characteristics: 1997–2017

	N studies	Pooled mean (95% CI)	Range
Percent white	11	0.64 (0.58, 0.71)	0.41 – 0.78
Percent Black	11	0.07 (0.05, 0.10)	0.02 – 0.30
Percent Hispanic/Latino	11	0.23 (0.19, 0.27)	0.13 – 0.36
Percent young (<25)	10*	0.36 (0.22, 0.50)	0.11 – 0.63
Percent female	11	0.34 (0.32, 0.36)	0.27 – 0.42
Percent urban Chicago	10	0.56 (0.45, 0.67)	0.28 – 0.80
Percent homeless	10	0.41 (0.31, 0.51)	0.15 – 0.68
Percent receptive syringe sharing	11	0.38 (0.33, 0.43)	0.27 – 0.49
Percent syringe mediated sharing	10	0.26 (0.23, 0.30)	0.17 – 0.38
Percent equipment sharing	9	0.65 (0.59, 0.71)	0.51 – 0.77
Percent exchange sex	10	0.17 (0.14, 0.19)	0.10 – 0.31
Mean # partners receptive syringe sharing	7	0.73 (0.59, 0.88)	0.52 – 1.29
Mean # partners distributive syringe sharing	5	1.02 (0.75, 1.30)	0.69 – 1.95
Mean # partners sharing equipment	6	1.89 (1.36, 2.43)	1.04 – 2.87
Mean total injection network size	6	13.75 (9.07, 18.44)	5.08 – 24.48
Mean injection sub-network size	5	4.31 (3.25, 5.36)	2.82 – 5.46

^*PSYCH study excluded: all under 25.