Background: Sexually transmitted diseases (STDs) enhance human immunodeficiency virus (HIV)-1 susceptibility, but few studies have examined the reciprocal effect of HIV-1 on STD acquisition.
Methods: Data from a prospective cohort study conducted among female sex workers in Mombasa, Kenya between 1993 and 2003 were used to determine the effect of HIV-1 infection on STD susceptibility. The cohort included 1215 HIV-1-seronegative women who underwent monthly HIV-1 and STD screening, of whom 238 experienced seroconversion to HIV-1 during follow-up. Andersen-Gill proportional-hazards models were used to compare the incidence rates for genital-tract infections (syphilis, genital ulcer disease [GUD], Neisseria gonorrhoeae infection, Chlamydia trachomatis infection, Trichomonas vaginalis infection, vulvovaginal candidiasis, and bacterial vaginosis) in HIV-1-seropositive versus HIV-1-seronegative women, after controlling for sexual behavior and other potential confounding factors.
Results: HIV-1 infection was associated with a significantly higher incidence of GUD (hazard ratio [HR], 2.8; 95% confidence interval [CI], 2.0-3.9), gonorrhea (HR, 1.6; 95% CI, 1.1-2.2), and vulvovaginal candidiasis (HR, 1.5; 95% CI, 1.3-1.8). The risks of GUD and vulvovaginal candidiasis increased with progressive levels of immunosuppression.
Conclusions: The increased incidence of genital-tract infections among HIV-1-seropositive women could promote the spread of both HIV-1 and other STDs, particularly in areas where these conditions are highly prevalent.