Gonorrhea as a risk factor for HIV acquisition.

Abstract

The role of gonorrhea in facilitating acquisition of HIV infection has only recently been studied. A previous nested case-control analysis in a cohort of female sex workers in Zaïre found a strong association between HIV seroconversion and prior gonorrheal infection. The objective of this study was to replicate the Zaïre study analysis in a cohort of 273 Cameroonian sex workers to determine whether gonorrhea increased the risk of HIV acquisition, and if the crude association between gonorrheal infection and HIV acquisition was weakened when the level of unprotected coitus was more carefully controlled. We conducted a nested case-control study of initially HIV-1-negative women (n = 273) followed prospectively (with monthly sexually transmitted disease check-ups and 3-monthly HIV-1 serology). As in Zaïre, cases (seroconverters, n = 17) were compared with controls (women who remained HIV-1-negative, n = 68) for incidence of gonorrhea and sexual exposure during the presumed period of HIV-1 acquisition. The association between gonorrheal infection and subsequent HIV acquisition was stronger in Zaïre than in Cameroon [crude odds ratios (OR), 6.3 versus 2.2]. In both the Zaïre and Cameroon data the crude OR were reduced (6.3 to 4.8, and 2.2 to 1.7, respectively) by controlling for risk factors including a dichotomous variable indicating irregular or no condom use. When this variable was replaced in the Cameroon data with a more precise continuous variable indicating the percentage of unprotected coital acts, the gonorrhea OR was further reduced to 1.4 (95% confidence interval, 0.4-4.9). These results suggest that in the Cameroon cohort, gonorrheal infection did not facilitate HIV acquisition, but that having gonorrhea was a marker for unprotected coitus that facilitated HIV acquisition. The data demonstrate how OR can be overestimated when imprecise dichotomous measures of unprotected coitus are used. Future studies should plan for better control of self-reported condom use.