Syphilis associated with recreational drug use, depression and high-risk sexual behaviour in men who have sex with men: a case-control study in China.

OBJECTIVE: We investigated syphilis prevalence among men who have sex with men (MSM) in China, as well as potential risk factors. Our principal hypothesis was that syphilis would be associated with the use of recreational drugs such as methamphetamines.
METHODS: From April to October 2013, we used several methods to recruit MSM in Qingdao, collecting demographic/behavioural information via self-administrated questionnaires. Trained health workers collected blood for the Treponema pallidum particle assay (TPPA) with positives confirmed by a toluidine red unheated serum test. We used an unmatched case-control study to identify factors that might predict syphilis infection using multivariable logistic regression.
RESULTS: We recruited 447 MSM who agreed to participate and who completed syphilis testing. Of 71 (15.9%) syphilis-positive MSM, 44 (62.0%) used drugs. Of 376 (84.1%) syphilis-negative MSM, 186 (49.5%) used drugs. We found a positive association with syphilis for any recreational drug use (crude OR (cOR) 1.7, 95 % CI 1.0 to 2.8), frequent methamphetamine use (cOR 2.4, 95% CI 1.1 to 5.3) and multiple drug use (adjusted OR (aOR) 3.4, 95% CI 1.3 to 9.2). Syphilis-positive men were more likely to have a higher physical depression score (aOR 5.2, 95% CI 1.1 to 24.4), be > 30 years old (aOR 2.7, 95% CI 1.5 to 4.8), report a prior STI (aOR 4.1, 95% CI 2.3 to 7.3) and report a sex party experience (aOR 2.2, 95% CI 1.1 to 4.4).
CONCLUSIONS: Recreational drug use, depression and high-risk sexual behaviours were associated with syphilis infection among MSM in China. Only a multifaceted approach is likely be effective in control of both syphilis and HIV . © Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.