Table 4a.

Multilevel analysis through hierarchical logistic regression. Factors associated with HCV seropositivity in 12 studies across Europe, 1990–2007 (N = 8479)

	Unadjusted OR		Adjusted OR
	Point estimate	95% CI	Point estimate	95% CI
Recruitment setting
Drug-treatment centres	1·0		1·0
Low-threshold services	0·9†	0·7–1·0	0·7	0·6–0·8
Others	1·0	0·9–1·1	0·8	0·7–0·9
Duration of injecting
<12 months	1·0		1·0
1–2 years	2·1	1·7–2·7	2·0	1·6–2·6
2–5 years	3·7	3·0–4·5	3·4	2·8–4·1
5–10 years	6·1	5·0–7·5	5·6	4·6–6·8
>10 years	11·6	9·5–14·2	11·5	9·3–14·1
Unknown	3·0	2·2–4·2	2·7	2·0–3·7
Injection last month
No	1·0		1·0
Yes	1·7	1·5–1·9	1·5	1·3–1·6
Unknown	1·8	1·6–2·0	2·3	1·4–1·6

OR, Odds ratio; CI, confidence interval.

^†P > 0·05. All other associations are significant with P < 0·001.