Background: Men who have sex with men (MSM) represent the largest HIV risk group in the United States. Sexual concurrency catalyzes HIV transmission in populations by increasing the indirect exposure of one's sex partners to one another. Although individual-level (egocentric) designs have demonstrated a high prevalence of concurrency among MSM respondents, methods are lacking for understanding the exposure implications for partners (dyads) reported in such studies.
Methods: A new technique for manipulating egocentrically collected partnership timing data to measure the degree to which respondents' patterns of concurrency and serial monogamy resulted in the indirect exposure of respondents' partners to other partners was developed. Two outcomes were constructed for each partner: any concurrent or serially monogamous exposure to another partner (any exposure) and any concurrent exposure to another partner, irrespective of serial monogamy (any concurrent exposure). Reports of unprotected anal intercourse (UAI) were incorporated to construct the outcomes of any UAI exposure and any concurrent UAI exposure. This method was applied to an online study of MSM aged ≥18 years, with comparisons made by partner's race–ethnicity, age, type, and meeting location.
Results: Among 4060 repeat partners of 2449 MSM, 73% had any exposure in the previous 6 months; 58% had any concurrent exposure. Among UAI partners, 37% had concurrent UAI exposure. Black UAI partners were more likely than whites to have any concurrent UAI exposure [unadjusted odds ratio (95% confidence interval) = 1.34 (1.05 to 1.70)], as were casual UAI partners relative to main partners [unadjusted odds ratio (95% confidence interval) = 4.37 (3.58 to 5.35)]. In adjusted models, black UAI partners were significantly more likely to have any UAI exposure, but not concurrent UAI exposure. Casual UAI partners remained more exposed by both outcomes.
Conclusions: Sex partners of MSM, particularly casual and black non-Hispanic partners, face a high degree of exposure to other partners.
*Department of Epidemiology, Rollins School of Public Health and
†Laney Graduate School, Emory University, Atlanta, GA;
‡Institute of Public Health, Georgia State University, Atlanta, GA; and
§Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA.
Correspondence to: Eli S. Rosenberg, PhD, Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Road Northeast, CNR 3025, Atlanta, GA 30322 (e-mail: firstname.lastname@example.org).
Supported by National Institute on Minority Health and Health Disparities (RC1MD004370), National Institute of Mental Health (R01MH085600), Eunice Kennedy Shriver National Institute for Child Health and Human Development (R01HD067111), and NIH P30AI050409—the Emory Center for AIDS Research.
The authors have no conflicts of interest to disclose.
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Received December 03, 2012
Accepted March 22, 2013