Venue-based affiliation networks and HIV risk-taking behavior among male sex workers

Abstract

Background: This study examined venue-based networks constituted by affiliation with gay bars and street intersections where male sex workers (MSWs) congregate to find their sexual/drug-sharing partners and network influence on risky sexual behavior (e.g., unprotected anal intercourse [UAI]) and HIV infection.

Methods: Data collected in 2003 to 2004 in Houston, Texas, consists of 208 MSWs affiliated with 15 gay bars and 51 street intersections. Two-mode network analysis was conducted to examine structural characteristics in affiliation networks, as well as venue-based network influence on UAI and HIV infection.

Results: Centralized affiliation patterns were found where only a few venues were popular among MSWs, and these were highly interdependent. Distinctive structural patterns of venue-based clustering were associated with UAI and infection. Individuals who shared venue affiliation with MSWs who engage in UAI were less likely to have UAI themselves. This suggests a downhill effect; that is, individuals compensate for their risk of infection by adjusting their own risk-taking behavior, based on their perceptions of their venue affiliates.

Conclusions: Venue-based HIV/AIDs interventions could be tailored to specific venues so as to target specific clusters that are more likely to engage in risky sexual behavior.

Figure 1

Affiliation network between 208 MSWs and 66 venues of bar and intersection Note: Blue circles represent MSWs, green squares represent bars, and grey triangles represent intersections. There are wide variations in the popularity of risky social places; a few bars and intersections are clearly dominant and attract many MSWs, and these popular venues (Int #31, Bar #2, and Bar #1) are located in the central position of the affiliation network.

Figure 2

Co-occurrence network of MSWs among venues without isolated venues Note: Each pair of venues is connected if they shared at least one common MSW. Green squares represent bars and grey triangles represent intersections. The width of the link represents the number of shared MSWs for each pair of venues (i.e., a thicker line represents more shared MSWs). By observation, it is clear that Bar #2 shares more MSWs with Bar #1, and with Int #31. Bar #2 also shares MSWs with Int #29 and Int #37 to a lesser extent. MSWs who hang out at Int #31 also affiliated with centrally located bars (i.e., Bar #2, Bar #1) but also with other bars that were marginally located.

Figure 3

Co-affiliation network consisting of 164 MSWs forming the component Note: Each pair of MSWs is connected if they share at least one common venue. Red represents HIV positive persons, blue represents HIV negative, and grey represents unknown HIV status, with circles representing those who engage in UAI, squares representing those who do not engage in UAI, and plus-signs representing unknown UAI status. Green and red boxes (A–D) represent a clustering of MSWs through affiliation with specific venues. Box A illustrates a cluster of 12 MSWs who affiliated with the centrally located venues of Int #31 and Bar #2, and their HIV status was almost evenly distributed while only one of them (blue circle) had UAI. Box B illustrates a cluster of 14 MSWs who affiliated with at least two venues of Bar #1 and Bar #2, and their HIV status was mostly negative while their UAI status was almost evenly distributed. Box C illustrates a cluster of 8 MSWs who affiliated with at least one of Bar #3, #4, and #15, most of whom were HIV positive and all of whom did not have UAI. Box D illustrates a cluster that contains 7 MSWs who self-reported as HIV positive and as having UAI (red circles).