Associations of gender identity with sexual behaviours, social stigma and sexually transmitted infections among adults who have sex with men in Abuja and Lagos, Nigeria

Introduction Sexual and gender minority populations are disproportionately affected by the global syndemic of HIV and other sexually transmitted infections (STIs). We hypothesized that transgender women (TGW) and non-binary individuals in Nigeria have more STIs than cis-gender men who have sex with men (cis-MSM), and that experiences of stigma and sexual practices differ between these three groups. Methods From 2013 to 2020, TRUST/RV368 enrolled adults assigned male sex at birth who reported anal sex with men in Abuja and Lagos, Nigeria. Participants were tested for STIs and completed questionnaires about sexual behaviours and social stigma every 3 months. Participants were categorized as cis-MSM, TGW or non-binary/other based on self-reported gender identity. Gender group comparisons were made of HIV, gonorrhoea and chlamydia prevalence and incidence; stigma indicators; and condom use during anal sex. Results Among 2795 participants, there were 2260 (80.8%) cis-MSM, 284 (10.2%) TGW and 251 (9.0%) non-binary/other individuals with median age of 23 years (interquartile range 20-27). HIV prevalence among cis-MSM, TGW and non-binary/other participants was 40.8%, 51.5% and 47.6%, respectively (p = 0.002). HIV incidence was 8.7 cases per 100 person-years (PY) (95% confidence interval [CI] 6.9-10.8), 13.1 cases/100 PY (95% CI 6.5-23.4) and 17.6 cases/100 PY (95% CI 9.8-29.0, p = 0.025), respectively. Anorectal gonorrhoea incidence was lower in cis-MSM than TGW (22.2 [95% CI 19.6-25.0] vs. 35.9 [95% CI 27.3-46.3]). TGW were more likely than cis-MSM to report being affected by stigma, including assault (47.2% vs. 32.3%), fear of walking around (32.4% vs. 19.2%) and healthcare avoidance (25.0% vs. 19.1%; all p < 0.05). TGW were more likely to report always using condoms than non-binary/other individuals (35.3% vs. 26.2%, p = 0.041) during receptive anal sex. Conclusions Sexual and gender minorities in Nigeria have heterogeneous sexual behaviours and experiences of social stigma that may influence the vulnerability to HIV and other STIs. There is a need for tailored interventions that acknowledge and are informed by gender. Further research is needed, particularly among understudied non-binary individuals, to better understand disparities and inform tailored interventions to improve outcomes among these communities.