Objective: To understand the characteristics of sexual partners and the influence of having multiple sexual partners on substance use among young male students man who have sex with men (MSM) in China, and to provide scientific basis for the prevention and control of HIV/AIDS among young MSM students. Methods: A mixed recruitment method of snowball sampling and respondent driven sampling was used to recruit young MSM students in Beijing and Tianjin, and a questionnaire survey was conducted among 220 participants from November to December 2019. Chi-square test and generalized linear model multi-factor Logistic regression were used to analyze the influencing factors of substance use before sexual behavior. Results: The average age of them was (22.39±2.57) years old, 84.5% of them were students, the average age of first sexual behavior was (18.83±2.45) years old, 44.1% of them had two or more sexual partners (including fixed sexual partners, temporary sexual partners and commercial sexual partners), 22.7% had more than one male fixed partner. After adjusting for age and education, having multiple sexual partners was risk factor for drinking alcohol before sex (aOR=2.97) or substance abuse (aOR=2.39). Having male temporary sexual partner was an risk factor in substance use before sexual behavior(OR=4.10). Conclusion The characteristics of sexual partners among young MSM students are complex, and the proportion of multiple sexual partners is high. Having fixed single sexual partner can reduce the risk of substance use before sexual behavior. AIDS prevention education for young MSM students should be further strengthened.

Objective: To identify the characteristics of social network and the association between ego-centric network and HIV status among young MSM Chinese students. Methods: The cross-sectional study was conducted in Chongqing, Tianjin, Harbin and Xi an city from April to December 2017 and from March to May 2018. A mixed recruitment method of snowball sampling and RDS approach was used to recruit participants who reported information on social network and received HIV test. The Multiple Regression Analysis method was used to for the analysis of association between ego-centric social network and HIV status of men who have sex with men (MSM) among young students. Results: The sample included 547 participants who nominated 1 088 social partners in total with average age of 13 to 60 years old. The MSM with different sexual orientation from their social members (aOR=0.38), embedded in a large network (aOR=0.63), with a high individual betweenness centrality (aOR=0.27) were at lower risk of HIV-positive status; while MSM who differed greatly in education level with their social members(aOR=1.60), existed in sexual networks(aOR=1.41), existed in the “risky networks” (aOR=1.88) , with high network density (aOR=1.91) and a high individual degree (aOR=4.10) had higher risk of HIV-positive status(P<0.05). Conclusion MSM with great difference in education level from social members, existed in sexual networks, with a large network density and a high degree were exposed to higher risk of HIV-positive status.