A Novel Social Network Approach to Measure Intersectional Stigma Among Latino Men Who Have Sex With Men in San Diego, California (NEXUS): Protocol for a Longitudinal Cohort Study

Background: Latino men who have sex with men (LMSM) account for a disproportionate and growing number of HIV diagnoses in the United States. Intersectional stigma remains a key driver of HIV inequities; however, most quantitative intersectional stigma measures are limited and do not consider the larger social context. Objective: NEXUS is a longitudinal cohort study that will use social network methods and theory to rigorously measure intersectional stigma among LMSM and quantify the longitudinal association between intersectional stigma and HIV prevention outcomes. Methods: We will prospectively enroll 500 HIV-negative LMSM in San Diego, California, and follow participants over 1 year. At baseline and every 6 months thereafter (Month 0, Month 6, and Month 12), participants will complete an interviewer-administered social network inventory and a self-administered survey to collect information on their social networks (alter types, size, and characteristics) and HIV prevention engagement (HIV testing and pre-exposure prophylaxis use), respectively. Information on HIV prevention engagement will also be abstracted from medical records. Intersectional stigma will be operationalized as a multilevel latent variable comprised of observed measures of anticipated and enacted stigma experienced by a participant from an alter toward the participant's Latino, masculine, and sexual identities. Multilevel structural equation modeling will be used to estimate the longitudinal association between intersectional stigma, HIV testing, and pre-exposure prophylaxis use, considering potential mediators and moderators. Results: NEXUS recruitment began in June 2021, and as of March 11, 2025, a total of 482 participants had been enrolled. Enrollment is planned to end by May 2025, with baseline results expected late 2025 and through the following year. Data collection for our prospective study aims is expected to be complete in June 2026, with data analysis and expected results published later that year. Conclusions: NEXUS will advance quantitative intersectional stigma measurement using a novel social network approach. This study will identify intervention targets to reduce HIV inequities among LMSM and mitigate the harms of intersectional stigma in this population.