Nathan John Lachowsky

Group membership and social connections play important roles in protecting people from stigmatized groups against the effects of discrimination on mental health. However, because people can belong to many groups, they may find themselves in situations where they experience stigmatization from others with whom they also share a stigmatized identity. We examine these intersectional experiences with a subsample of sexual minority men of color from a larger cohort study focused on sexual minority men’s health and wellbeing in Canada’s three largest cities (N = 314, nvisits = 725). We examine (i) whether experiences of racism from other sexual minority men and homophobia from other people of color affects the types of partners people seek out and (ii) whether having partners from a similar ethnoracial background protects against the effects of discrimination on mental health. We found that neither racism from other sexual minority men (including sexual racism) nor homophobia from people of color affected whom participants sought out as sexual partners. Having more partners of the same ethnoracial background had mixed protective effects. The effects of racism from sexual minority men (but not sexual racism) on mental health were attenuated among participants who reported more ethnoracial ingroup partners. However, having more partners exacerbated the effects of homophobia from other people of color. These effects were limited to partners of the same race or ethnicity, and not to partners of color in general. These findings highlight the importance of attending to intraminority intersectional experiences and nuances of the effects of group membership across different forms of stigma.

HIV treatment attitudes and HIV PrEP are associated with sexual behavior that elevates the risk for bacterial STIs (B-STIs) among gay, bisexual and other men who have sex with men (GBM). Using a longitudinal multi-site study (Engage Cohort Study, 2017-2024), we modelled direct and indirect within- and between-person effects of HIV treatment attitudes and PrEP use on condomless anal sex (CAS) and incident B-STIs among 1863 HIV-negative GBM. We modelled up to four years of follow-up visits using multi-level mediation analysis, with CAS as a mediating variable between HIV treatment attitudes and PrEP use on incident B-STIs. We found direct within-person effects of HIV treatment attitudes and PrEP use on incident B-STIs, such that participants were more likely to report incident B-STIs at time points if they reported using PrEP and being more optimistic about HIV treatments; there were no indirect within-person effects through CAS. In contrast, we found both direct and indirect between-person effects. Specifically, participants who reported more PrEP use or who were more optimistic about HIV treatments over the course of the study were more likely to report incident B-STIs. Further, these effects were partially mediated by CAS. Given that we found within-person PrEP use is associated with increased CAS and STIs, and the general increase in adoption of PrEP over time, there is a need to expand biomedical intervention programs for B-STIs prophylaxis by integrating them with social and informational interventions about B-STIs risks, especially for GBM who use HIV PrEP.

Background: We compared the prevalence of vaccine-preventable anal human papillomavirus (HPV) types among gay, bisexual, and other men who have sex with men (GBM) living in large cities in Canada from 2019 to 2021 by age and human immunodeficiency virus (HIV) status. Methods: Sexually active GBM ≥16 years were recruited in Montreal, Toronto, and Vancouver using respondent-driven sampling (RDS). Participants self-reported HPV vaccination and self-collected anal HPV specimens. We estimated the prevalence of vaccine-preventable types for participants during the 2019–2021 period. We report RDS-II-weighted prevalence and confounder-adjusted prevalence ratios (aPRs) comparing vaccinated (≥1 dose) and unvaccinated GBM using multivariable Poisson regression. Results: Among 1519 participants aged 18–83 (median 35 years), 17.6% had HIV, and 62.2%, 40.2%, and 15.0% were vaccinated in the 16–26-, 27–45-, and ≥46-year groups, respectively. Among GBM 16–26 years, HPV6/11/16/18 prevalence was lower among those vaccinated ≤23 years (aPR = 0.40, 95% CI: .20–.77), ≥3 years since first dose (aPR = 0.39; 95% CI: .18–.85), and those with ≤5 years of sexual activity before vaccination (aPR = 0.47; 95% CI: .25–.89). HPV6/11/16/18/31/33/45/52/58 prevalence was lower among those vaccinated ≤26 years in GBM aged 27–45 years (aPR = 0.81, 95% CI, .61–1.08), though this did not reach statistical significance. Conclusions: Five years after implementation of Canadian HPV vaccination programs for younger GBM, anal HPV prevalence was lower among those vaccinated at younger ages and near sexual debut.

Group sex, which encompasses sexual activity among more than two people, is prevalent across diverse genders and sexualities. For many of its participants, group sex is an important source of pleasure and belonging. However, it is most often studied in the context of STI risk and related harm reduction, which isolates STI-related harm reduction behaviors from broader community norms and culture, obscuring important community dynamics. In the present study, we investigated a broad range of harm reduction practices employed by group sex participants in southwestern British Columbia, Canada. Through thematic analysis of interviews with 20 participants, we identified diverse harm reduction strategies enacted before, during, and after events to mitigate physical, emotional, and social risks. These strategies included vetting attendees in advance, establishing consent norms (e.g., consent circles, color-coded bracelets), promoting STI prevention (e.g., regular testing, barrier usage), and maintaining privacy. Findings highlight a collaborative approach to harm reduction, emphasizing both community trust and individual responsibility/accountability, reflecting a broader culture of care. This work broadens the scope of harm reduction in group sex contexts beyond STI prevention, offering insights applicable to broader sexual wellness initiatives and discussions of consent and safety in sexual communities.

Objectives: Doxycycline as post-exposure prophylaxis (doxy-PEP) has emerged as an efficacious strategy to reduce Chlamydia trachomatis (C. trachomatis) , Neisseria gonorrhoeae (N. gonorrhoeae) and syphilis (sexually transmitted infections (STIs)) among gay, bisexual and other men who have sex with men (GBM). There is a need to identify prescribing criteria that maximise the number of STIs averted while minimising excessive use. Design: In this prospective longitudinal cohort study with repeated measures and biobehavioural data collection, participants completed a questionnaire and tested for STIs at each visit. Setting: Community-based, population-level study conducted in three large Canadian cities between February 2017 and July 2023. Participants: 2449 GBM were recruited through respondent-driven sampling (RDS); 1998 had ≥1 follow-up visit, contributing 7551 person-years of observation. Eligible participants were aged ≥16 years, cis- or transgender men, reported sex with another man in the past 6 months and resided in Montreal, Toronto or Vancouver. Primary and secondary outcome measures: Adjusted rate ratios (aRR) of STIs, accounting for RDS recruitment, loss to follow-up and confounding were estimated using generalised estimating equations (GEE) Poisson regression. For identified STI risk factors, the proportions of STIs averted through doxy-PEP prescription (based on the efficacy of doxy-PEP for each bacterial STI) and the number needed to treat (NNT) for 1 year to avert one STI, assuming 100% adherence, were calculated. Results: Among 1998 participants, the combined incidence rate of any C. trachomatis , N. gonorrhoeae and syphilis infection was 29.5 (95%CI 27.3 to 31.9) per 100 person-years. STI risk factors that had the most impact as doxy-PEP criteria were history of any of the three STIs in the past 12 months (P12M) (aRR=2.0, 95% CI 1.8 to 2.2, 36% STI averted, NNT=2.1); ≥10 male sexual partners in the past 6 months (P6M) (aRR=3.8, 95% CI 3.0 to 4.9, 41% STI averted, NNT=2.4); HIV-pre-exposure prophylaxis (PrEP) use P6M (aRR=1.7, 95% CI 1.5 to 2.0, 29% STI averted, NNT=2.5); use of any chemsex-related substance P6M (aRR=1.2, 95% CI 1.1 to 1.4, 28% STI averted, NNT=2.6); and group sex event attendance P6M (aRR=1.2, 95% CI 1.1 to 1.3, 27% STI averted, NNT=2.3). Reporting≥10 male sex partners P6M represented the most useful criterion for syphilis prevention (52% syphilis infections averted, NNT=20). Prescribing doxy-PEP to GBM having any of the following STI risk factors, namely, ≥1 bacterial STI P12M, ≥10 male sex partners P6M, or HIV-PrEP use P6M, would substantially increase the proportion of all STI diagnoses potentially averted (60%) with minimal increase of the NNT (2.7). Conclusion: This work informs on the impact of various doxy-PEP clinical prescribing criteria and demonstrates the benefit of focusing on any of the following three criteria: ≥1 bacterial STI P12M, ≥10 male sex partners P6M or HIV-PrEP use P6M.

Research on diversity within group sex communities in Canada tends to focus on gender, sexuality, and body size as indicators of inclusion and acceptance. Racial/ethnic diversity are notably absent from these discussions; in this study, we explored perceptions and experiences of race and racism in group sex spaces. We conducted two annual individual interviews with group sex participants living in southwestern Canada. Of our 20 participants, 40% identified as people of color (POC). We worked with a community advisory board of group sex participants/organizers on participant recruitment, interview questions, and data analysis. Through reflexive thematic analysis, we constructed three themes. In themes 1 and 2, we discuss barriers to entry for POC and manifestations of racism within group sex spaces, respectively; these include lack of racial diversity, white ignorance, cultural appropriation, and desirability politics. Some POC described being fetishized because of race, which non-POC downplayed as simply being "kinky." In theme 3, we discuss change-making barriers, such as defensiveness, and change-making opportunities, such as integrating anti-racism into existing harm reduction practices. Participants expressed that community leaders and event organizers need to shift their responses to racism and how they create and manage group sex spaces. These results advance broader discussions of sexual racism and white defensiveness, as well as opportunities to advance anti-racism within group sex spaces and communities.