Peripheral Positions and Reachability of Casual Sexual Partners in Egocentric Networks among Sexual and Gender Minorities

BACKGROUND: Casual sexual partners (CSP) involve non-monogamous partnerships, limited personal disclosure, and sexual behaviors that could facilitate HIV transmission. Their peripheral positions in social networks may limit intervention reach but also create unique bridging opportunities for prevention efforts. METHODS: Egocentric network data were collected from sexual and gender minority participants (egos) in Charlotte, North Carolina from 2023-2025. We compared CSPs' demographic characteristics and structural positions in networks with those of other social contacts (alters), including established sexual partners (ESPs), and non-sexual alters (NSAs). Factors associated with connectivity between NSAs and sexual partners were examined using dyadic and triadic analyses. RESULTS: Having CSPs was associated with having HIV, larger networks, and more sexual partnerships. Both casual and established sexual partners provided limited social support to egos and occupied peripheral positions with reduced reachability within egocentric networks. NSAs connected to CSPs showed lower racial homophily with their egos compared with those connected to established partners but were more likely to provide physical or health support. NSAs who were: socially closer to egos (adjusted odds ratio [aOR]=6.13, 95% confidence interval [CI], 1.26-62.24); not family members (aOR=0.02, 95% CI, 0.00-0.45); and living within 5 miles (aOR=6.92, 95% CI, 1.22-55.53) were more likely to know egos' CSPs. In sensitivity analysis that defined longer-standing sexual partners as CSPs, our main findings persisted. CONCLUSIONS: Future interventions could consider integrating key NSAs into peer-led strategies to enhance HIV/STI prevention, as their connections within egocentric networks may help facilitate engagement with sexual partners.