Syndemic Conditions and Their Association with HIV/STI Sexual Risk Behaviors Among Transgender Women and Cisgender Men Sex Workers in Catalonia: The SexCohort Project

Background: Transgender women and cisgender men sex workers are vulnerable to HIV and sexually transmitted infections (STIs). This study aimed to explore in depth the prevalence of syndemic conditions and their association with the sexual risk behaviors for HIV/STI acquisition in cis men and trans women sex workers in Barcelona (Catalonia, Spain).

Method: We conducted a study between 2014 and 2018 to determine whether syndemic conditions (frequent alcohol consumption and polydrug use (> 2) during sex with clients; experience of violence; and lack of healthcare access) are associated with HIV/STI sexual risk behaviors. A "syndemic index" was calculated based on the cumulative number of syndemic conditions (0 to 4).

Results: In the last year (2018), 78.8% of cisgender men and 68.1% of transgender women reported at least one syndemic condition. The most prevalent syndemic factor in both cisgender men and transgender women was violence (38.8% and 43.6% respectively). In multivariable analysis, an association was found between condomless anal sex and violence (aOR = 1.81), and frequent alcohol consumption and violence with reporting > 10 clients/week (aOR = 2.73 and 1.88, respectively). The higher the number of syndemic factors, the greater probability of having > 10 clients/week and reporting condomless anal sex with clients.

Conclusion: Psychosocial conditions have a syndemic effect on risky sexual behaviors highlighting the need for a more holistic approach to HIV/STI prevention targeting these populations.