Incidence and risk factors on HIV infection among injection drug users in Dehong prefecture area of Yunnan province

OBJECTIVE: To determine the incidence and risk factors on HIV infection among injection drug users (IDU) in Dehong prefecture area of Yunnan province. METHODS: An epidemiological cohort of HIV-negative IDU had been developed and followed since October 2004. HIV new infections and related behaviors had been investigated every six months. RESULTS: By the end of 2008 760 HIV-negative IDU had been recruited and followed for a total of 1153.6 person-years. 47 new HIV infections were identified with an overall incidence of 4.07/100 person-years during the follow-up period. The HIV incidence was 4.45/100 person-years during 2004 - 2006 4.50/100 person-years in 2007 and 2.54/100 person-years in 2008. Both the behavior of drug injection and the HIV incidence among the cohort had substantially decreased during the follow-up period. Multiple regression analysis using Cox proportional hazard model indicated that people with Jing-po ethnicity (Hazard ratio HR = 2.56 95%CI: 1.06 - 6.19) and other minorities except for Dai (HR = 3.26 95%CI: 0.89 - 11.96) were at higher risk for HIV infection than the people with Han ethnicity. People injecting drugs with (HR = 2.27 95%CI: 0.98 - 5.25) or without (HR = 5.27 95%CI: 2.25 - 12.34) needle sharing were at higher risk for HIV infection than those reporting having no drug injection behavior during the follow-up period. CONCLUSION: Both the behavior of drug injection and the HIV incidence among former IDU in Dehong prefecture area of Yunnan province had been decreasing during the four years. However needle sharing remained the most important risk factor for HIV new infection among IDUs. IDUs with different ethnicities seemed to have different risks towards HIV infection.