Network mixing and network influences most linked to HIV infection and risk behavior in the HIV epidemic among black men who have sex with men

Abstract

Objectives: We evaluated network mixing and influences by network members upon Black men who have sex with men.

Methods: We conducted separate social and sexual network mixing analyses to determine the degree of mixing on risk behaviors (e.g., unprotected anal intercourse [UAI]). We used logistic regression to assess the association between a network "enabler" (would not disapprove of the respondent's behavior) and respondent behavior.

Results: Across the sample (n = 1187) network mixing on risk behaviors was more assortative (like with like) in the sexual network (r(sex), 0.37-0.54) than in the social network (r(social), 0.21-0.24). Minimal assortativity (heterogeneous mixing) among HIV-infected men on UAI was evident. Black men who have sex with men reporting a social network enabler were more likely to practice UAI (adjusted odds ratio = 4.06; 95% confidence interval = 1.64, 10.05) a finding not observed in the sexual network (adjusted odds ratio = 1.31; 95% confidence interval = 0.44, 3.91).

Conclusions: Different mixing on risk behavior was evident with more disassortativity among social than sexual networks. Enabling effects of social network members may affect risky behavior. Attention to of high-risk populations' social networks is needed for effective and sustained HIV prevention.

FIGURE 1—

Total generated network sample among Black men who have sex with men (MSM) (n = 983): Chicago, 2010. Note. Stratification of MSM respondent confidant network into social and sexual network was based on respondent characterization of confidants as sexual partners or not. ^aRelationship type missing for 5 network members.

FIGURE 2—

Mixing within social and sexual networks among Black men who have sex with men, by risk behavior and HIV status: Chicago, 2010. Note. AC = assortativity coefficient; UAI = unprotected anal intercourse. The AC is calculated from the mixing matrix—the proportion of total ties in a cross-tabulation of ties between people who do and do not have a risk attribute. Social network n = 716. Sexual network n = 262. Nodes and error bars within each behavior category indicate the AC for all dyads (social or sexual) in the sample, further stratified by HIV status of participants. An AC of 1 would indicate perfectly assortative mixing (e.g., respondents who practice a behavior only have sexual relations with or are social with network members who also practice that behavior), whereas respondents who do not practice the behavior only have sexual relations with or are social with network members who also do not practice the behavior. The combined AC indicates a general trend of increasing assortativeness for riskier behaviors (starting with sex-drug use and ending with HIV status [or serosorting]).