P3.31 High risk behaviours and syphilis/hiv infection among men who have sex with men aged 50 years and older in shenzhen, china

Introduction The national average HIV prevalence among men who have sex with men in China increased from 1.4% in 2005 to 8.0% in 2015. There is a significant increase in the number of HIV new infections in individuals over 50 years of age in China and other countries. In China the prevalence of syphilis/HIV infection among MSM over 50 years is increasingly high but few reports pay attention to it. Our study was to investigate the high risk behaviours and syphilis/HIV infection among men who have sex with men over 50 years in Shenzhen, China. Methods Snowball sampling and respondent driven sampling were used to recruit MSM from 2009 to 2015 in Shenzhen, China. Questionnaire-based interviews were conducted on a one-on-one basis to collect data of socio-demographic information, HIV testing history, history of blood donation in recent two years, self-identified sexual orientation, role in homosexual behaviour, ever being money boy(MB) and clients of MB. 5 ml blood samples were taken and tested for treponema pallidum and HIV antibodies. Results Among the total of 5221 MSM recruited, 186 (3.56%) cases were aged 50 years and older. MSM aged 50 years and older were more likely to get married, have high school or below level of education, have monthly income less than 3000 Yuan, work in service industry or be jobless. Most of them never used condoms for every act with female sexual partners. About one-third had more than 5 anal sexual partners in recent six months. They had higher rate of never using condoms when having anal sex compared with MSM aged less than 50 years. The rate of syphilis, HIV infection and syphilis-HIV co-infection among MSM aged 50 and older were 1.8917, 1.7387, 2.0365 times as high as that among MSM aged less 50 years, respectively. Conclusion MSM aged 50 and older had higher prevalence of syphilis and HIV and acted as bridge population to transmit syphilis/HIV. It is necessary to carry intervention measures targeted to them.