HIV prevalence and factors associated with HIV infection among male injection drug users under 30: a cross-sectional study in Long An, Vietnam

Table 2 Characteristics of subjects related to drug use according to HIV serostatus, and odds ratios associated with HIV seropositivity (n = 248)

Characteristics	HIV (+) (n = 80)	HIV (-) (n = 168)	p-value*(χ² test)	OR^†	95%CI	p-value
Year they started injection drug
-1999	20 (25.0)	55 (32.7)	0.22	1	(reference)
2000-	60 (75.0)	113 (67.3)		1.56	0.83 – 2.91	0.17
Age when they started injection drug (years)
10–17	24 (30.0)	44 (26.2)
18–20	36 (45.0)	67 (39.9)	0.23	NA^‡
21–24	13 (16.3)	47 (28.0)		NA
25–29	7 (8.8)	10 (6.0)		NA
Duration of injection drug use (years)
< 1	14 (17.5)	41 (24.4)		1	(reference)
1 to 2	46 (57.5)	73 (43.5)	0.12	1.83	0.87 – 3.84	0.12
3-	20 (25.0)	54 (32.1)		1.05	0.45 – 2.44	0.11
Frequency of drug use (previous month)
<1/day	31 (38.8)	87 (51.8)	0.055	1	(reference)
≥1/day	49 (61.3)	81 (48.2)		1.70	0.98 – 2.96	0.058
Sharing needles and syringes (previous month)
Never	58 (72.5)	140 (83.3)		1	(reference)
Sometimes	18 (22.5)	22 (13.1)	0.26	2.05	0.99 – 4.08	0.054
About half	2 (2.5)	3 (1.8)		1.75	0.27 – 10.88	0.57
Every time/Almost every time	2 (2.5)	3 (1.8)		1.66	0.26 – 10.29	0.61
Injection drug use in other cities (12 months)
No	51 (63.8)	126 (75.0)	0.067	1	(reference)
Yes	29 (36.3)	42 (25.0)		1.82	1.01 – 3.26	0.046

n indicates number; OR, odds ratio; CI, confidence interval; IDU, injection drug user.
*: Differences in proportions between HIV (+) IDUs and HIV (-) IDUs were tested by χ² tests.
†: Age-category-adjusted odds ratio.
‡: Not applicable due to strong correlation between ages at time of survey and when they started injection drug use.

ISSN: 1471-2458