Sexual risk behaviours and population size estimation of men who have sex with men in Bhutan: a cross-sectional survey

Introduction Globally, men who have sex with men (MSM) have a higher HIV risk, with transmission rising in many Asian countries. Limited information on MSM in Bhutan hampers HIV prevention efforts. This study estimates the size of the MSM population and examines risk behaviours at the district and national levels. Methods A cross-sectional community-based survey and population size estimation exercises were conducted in Bhutan from November 2019 to December 2020. MSM in 9 of 20 districts in Bhutan were recruited using a hybrid sampling approach, combining peer-referral snowballing, venue-based outreach and online recruitment through MSM-oriented platforms. A standardised face-to-face questionnaire collected demographic and HIV-related data, while population size estimation methods, including the service multiplier, unique object multiplier and wisdom of the crowds, complemented the survey. The study was approved by the Research Ethics Board of Health of Bhutan, and verbal informed consent was obtained. Results Among 273 MSM surveyed, 85.7% had their first sex before age 15; 17.4% sold sex and 22.1% exchanged sex for goods. Only 40.9% had tested for HIV in the past year, 25.0% attended HIV education, 18.5% faced discrimination at health services and 22.0% experienced violence for being MSM. Bayesian synthesis estimated 1463 MSM (95% CI 1006 to 2030) in the study area, with a national extrapolation of 1726 MSM. Conclusions Our study estimated that MSM comprise approximately 1.58% of urban men in Bhutan who originate from diverse geographic areas and sociodemographic backgrounds. Findings inform HIV and sexually transmitted infection (STI) services for MSM through target setting and effective resource allocation, emphasising the need for targeted HIV prevention addressing low testing rates and high-risk behaviours. Overcoming healthcare discrimination requires tailored interventions and stronger collaboration between health authorities and MSM communities.