Iskandar et al. BMC Public Health 2010, 10:472 http://www.biomedcentral.com/1471-2458/10/472 The use of methadone or buprenorphine among cIDUs was higher compared to fIDUs. The EuropASI question- naire does not allow us to verify whether this was as part of substitution treatment or not. Both drugs are officially registered in Indonesia for substitution treatment but illegal use is quite common. Buprenorphine injection has been reported in many countries including Indonesia, and can be regarded as a response to inadequate care, rather than simply as misuse [25]. Alcohol abuse was common, and was associated with risky sexual behavior, as has been reported previously [26]. The same has been reported for methamphetamine and amphetamine use [27], but this seems still relatively rare in this setting. Our study also showed a high preva- lence of tattooing and piercing in former and current IDUs, both of which have may lead to transmission of HIV and viral hepatitis [8,9,28]. This study suffers form the limitations of a cross-sec- tional study in a population which is difficult to reach, and the question is therefore how representative the samples are. By using RDS, we tried to minimize this risk [12,29]. Numerical simulations have shown that the possible bias, even if the seeds are not drawn randomly, is extremely small (0.3%) for all sample sizes greater than 200 [12]. Still, some IDUs who are not in the social networks with these participants can not be recruited through respondent driven sampling [30]. Conclusions In conclusion, this study from Indonesia shows that for- mer IDUs, when compared to current IDUs, may have similar high HIV prevalence rates and high sexual risk behavior. Specific programs focusing on the reduction of sexual risk behavior are needed among former and cur- rent IDUs, in order to prevent further transmission to the general community. Drug-use treatment and inter- ventions that examine the relationship between drug use and sexuality should be conducted. In addition, earlier HIV treatment may lower transmission among IDUs by reducing the ‘community viral load’[31]. We have recently shown that patients with a history of injecting drug use in our setting have a similar clinical and virolo- gical response to anti-retroviral treatment compared to non-IDUs [19]. Finally, evidence-based prevention should also be targeted at schoolchildren and young adolescents as injecting drug use starts at an early age in this setting. Acknowledgements We would like to thank Prof. Tri Hanggono Ahmad, Dean of the Medical Faculty Padjadjaran University for encouraging and accommodating research in Padjadjaran University. We also thank the interviewers, Rinske de Graaff Stoffers, Mark Holland, staffs and ORC from Salam Primary Health Center. Rumah Cemara, Bahtera, PKBI, and Grapiks are thanked for their valuable help. Page 6 of 7 Financial support SI received fellowship from Radboud University, The Netherlands. Financial support was provided by ‘IMPACT’ (Integrated Management of Prevention And Care and Treatment of HIV/AIDS), a collaborative research and implementation program of Padjadjaran University, Bandung, Indonesia; Maastricht University and Radboud University, Nijmegen, the Netherlands; and Antwerpen University, Belgium. IMPACT is funded by the European Commission (SANTE/2005/105-033), and contracted by CORDAID. Author details 1Department of Psychiatry, Faculty of Medicine, Padjajaran University/Hasan Sadikin Hospital, Bandung, Indonesia. 2Health Research Unit, Faculty of Medicine, Padjadjaran University/Dr. Hasan Sadikin Hospital, Bandung, Indonesia. 3Department of Health Education and Health Promotion, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands. 4Department of General Internal Medicine and Nijmegen Institute for Inflammation, Infection and Immunity, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. 5Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Nijmegen, the Netherlands. Authors’ contributions SI made and carried out the research protocol, performed the statistical analysis, and drafted the manuscript. DB and LP participated in making the research protocol. TH and IS participated in the design of the study. 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