African American women have high rates of most sexually transmitted infections (STIs), including HIV. STIs have been associated with increased HIV transmission risk.

Methods: Two hundred twenty-eight black women who used drugs completed a structured questionnaire in a central Brooklyn, NY-based research center between March 2003 and August 2005. Women were screened for HIV, herpes simplex virus-2, syphilis, gonorrhea, chlamydia, and trichomoniasis. This analysis determined if STIs cluster within individuals and if clustering and sex practices or partnerships differ by HIV status.

Results: Thirty-eight (17%) women tested HIV seropositive and STI prevalence was herpes simplex virus-2 (79%), trichomoniasis (37%), chlamydia (11%), and gonorrhea (2%). Few women knew themselves to be infected with STIs other than HIV. Excluding HIV, the mean number of STIs per woman was 1.3 (SD 0.7). HIV-infected women were significantly more likely than uninfected women to have multiple positive screens (1.6 vs. 1.2, P = 0.002). Women reported having both lower and higher risk sex partners. HIV-infected women were 2 times more likely than uninfected woman to report current sex work (P = 0.05), the only difference in sex risk. In a linear regression model, crack cocaine use was uniquely associated with multiple positive STI screens, excluding HIV (P = 0.002).

Conclusions: Several STIs, including HIV, seem to be endemic among black women who use drugs in this community. In addition to the known geographical clustering of HIV and STIs, STIs were also found to cluster at the individual level. Multiply STI infected individuals may unknowingly, but efficiently, contribute to high STI and HIV rates.