Clustering analysis of sexual behavioral patterns and risk of sexually transmitted infections in Chinese men who have sex with men.

INTRODUCTION

This study identifies clusters in Chinese men who have sex with men (MSM) by sexual behavioral patterns and defines high-risk subgroups for gonorrhea, chlamydia, and syphilis infections.

METHODS

We conducted a longitudinal study of Chinese MSM from November 2020 to January 2022, collecting weekly data over 12 consecutive weeks on sequential sexual act patterns and testing for gonorrhea, chlamydia, and syphilis infections. Hierarchical clustering identified sexual behavior patterns, and survival analysis estimated infection incidence within each cluster.

RESULTS

We identified three main clusters (n = 91, 100, 62), one small cluster (n = 8) and 41 unclustered participants. Participants in cluster 1 engaged in both insertive and receptive roles in oral, anal sex and rimming during sexual encounters. Cluster 2 participants predominately performed insertive sexual acts, while cluster 3 performed receptive sexual acts. During follow-up, cluster 1 exhibited a significantly higher incidence of overall gonorrhea infection (581.51/100,000 person-days), pharyngeal (355.45/100,000 person-days), anorectum gonorrhea (487.63/100,000 person-days) and syphilis (17.19 %) while comparing with cluster 2 and 3. Consistently, cluster 1 was significantly more likely to engage in kissing (40.08 %) and insertive rimming (6.77 %) and receptive rimming (7.18 %), in sexual act pairs such as 'receptive oral sex-insertive oral sex' (8.71 %), 'receptive rimming-insertive anal sex' (4.59 %), 'kissing-receptive oral sex' (13.62 %), 'insertive anal sex-receptive anal sex' (5.38 %) and 'insertive rimming-receptive rimming' (6.83 %).

CONCLUSION

Sexual role preference is a significant factor in clustering Chinese MSM. Those who assume both insertive and receptive roles demonstrate a substantial higher risk of gonorrhea and syphilis infections.