Iskandar et al. BMC Public Health 2010, 10:472 http://www.biomedcentral.com/1471-2458/10/472 34 questions divided in three sub-scales which measure frequency of current risk behavior related to blood to blood transfer (20 questions); sexual practices (8 ques- tions); and other skin penetration activities (6 questions) in the previous month. With respect to possible blood to blood transfer, information is collected about contact with contaminated needles and syringes, other drug injecting equipment sharing and involvement of other people in the drug preparation and injecting process. Questions related to sexual risk behavior address unpro- tected vaginal, anal, oral, and manual sex with other people, with or without lubricant, and during menstrua- tion or not. Other questions address skin penetration risk behavior (tattooing and piercing), and shared use of toothbrush, razor, and personal hygiene equipment. The administration time for the instrument is short (around 15 minutes), and it has been shown good reliability and validity [17,18]. Data analysis and statistics A former IDU (fIDU) was defined as a person who reported to have injected an illicit drug at some point in his/her life, but not to have injected any drugs in the six months prior to the interview (17, 18). A current IDU (cIDU) was defined as a person who reported that he/ she had injected any type of illicit drug in the six months prior to the interview [6,10]. Data were analyzed both descriptively and inferentially. Descriptive data are presented in terms of percentage, mean, and standard deviation. Subjects engaging in at least one risk taking behavior in a subscale of the BBV-TRAQ were regarded as taking risks in that domain. Data were analyzed infer- entially for differences between fIDUs and cIDUs. Pear- son Chi-Square was used for dichotomous data and the Mann-Whitney test for non-parametric continuous data. All tests were two-sided, with a P-value of 0.05 or less considered to indicate statistical significance. Analyses were performed with the use of SPSS, version 11.5. Results Characteristics of IDUs in Bandung A total of 210 IDUs were recruited, of whom 194 were men (92%), 92 were fIDUs (44%), and 118 were cIDUs (56%). Thirty-three out of 92 fIDUs (35.9%) were invited by cIDUs, while 34 of 118 cIDUs (30.3%) were invited by fIDUs, showing extensive social linking between the two groups. Most of the demographic characteristics of fIDUs and cIDUs did not differ, except for the length of injecting drug and percentage of those who developed AIDS (table 1). The mean age was 28 (±4) years and most participants had graduated from senior high school and had been employed at some point in the last 3years. They had started using drugs at a young age (14 (± 3) years). Injection of drugs had typically started 4 years Page 3 of 7 after non-injecting drug administration, and the period of injecting drugs averaged 7 (± 4) years. Three quarters of the participants had been tested for HIV and among those tested 63% reported to be HIV-infected. There was no significant association between the cumulative years of drug injecting and HIV-status (P = 0.47). One third of those who were HIV-infected reported to have developed AIDS. Although cIDUs had injected for a longer period than fIDUs, HIV-infected individuals in the latter group more commonly reported having AIDS (44% vs 18%; P = 0,01). The most used substance by all participants was her- oin. Ninety four percent of the total participants had at some point used heroin regularly (at least three times a week or for two consecutive days in a week for more than 6 months). The other most used substances were cannabis, benzodiazepines, and alcohol. More than three quarters of participants had ever used or still used dif- ferent drugs at the same time (poly drug use) and 70% of the total IDUs had ever used or still used ampheta- mine or methamphetamine regularly (median 2 years (range less than 1 year until 15 years). In the last 30 days, cIDUs had typically used more drugs than fIDUs but neither cIDUs nor fIDUs reported total abstinence in the last 30 days. The most used sub- stances by fIDUs in the last 30 days were alcohol, licit or illicit methadone/buprenorphine while cIDUs mostly used licit or illicit methadone/buprenorphine, heroin, benzodiazepines, and cannabis (table 2). Licit or illicit use of methadone or buprenorphin cannot be differen- tiated with the ASI. Risk behavior related to transmission of blood-borne viruses Blood to blood transfer risk behavior was reported by 76% of cIDUs and 13% of fIDUs (X2 = 82,73; p < 0,01) (table 3). Risk behavior of ninety cIDUs (76%) was related to sharing of contaminated drug injecting equipment. Current IDUs often reported behavior associated with a very high risk of transmission of blood-borne pathogens, including injecting with another person’s used needle or syringe (reported by 15% of cIDUs), re-use of a needle or syringe taken out of a shared disposal/sharps container without using bleaching (9%), and sharp injuries from another per- son’s used needle/syringe (15%). cIDUs also reported behavior associated with a somewhat lower risk of transmission. For example, they had exposure to con- taminated drug injecting equipment included shared use of a tourniquet (43%); injecting a drug prepared with water previously used by another person (41%); handling another person’s used needle or syringe when wounded at his or her hand (34%); wiping his/her own injection site with an object that had been used by