title: Internet-based partner selection and risk for unprotected anal intercourse in sexual encounters among men who have sex with men: a meta-analysis of observational studies.
abstract: BACKGROUND
  Men who have sex with men (MSM) who identify sex partners over the internet are more likely than other MSM to report having unprotected anal intercourse (UAI). It is unclear whether the internet facilitates pursuit of high-risk sex or whether MSM seeking sex online are a higher-risk population than other MSM. To summarise evidence as to whether internet-based partner selection predisposes MSM to high-risk behaviour, we conducted a meta-analysis of observational studies comparing MSM's UAI risk in online-initiated encounters to their UAI risk in offline-initiated encounters.
  
  
  METHODS
  We systematically searched published, peer-reviewed literature to identify studies reporting MSM participants' engagement in UAI with online-identified and offline-identified male partners. We calculated pooled odds ratios for any UAI and for seroadaptive UAI practices with partners identified online relative to partners identified offline.
  
  
  RESULTS
  We included 11 studies representing 39,602 sexual encounters. Odds for any UAI, seroconcordant UAI and serodiscordant UAI with strategic positioning were higher in online-initiated than offline-initiated encounters. Odds for UAI in group sex were higher in online-initiated encounters only among HIV-positive MSM. Effect sizes for all outcomes were greater among HIV-positive than HIV-negative MSM. Effect sizes were greatest when bathhouses, saunas and sex resorts were treated as offline comparison venues.
  
  
  CONCLUSIONS
  Encounters initiated online have elevated odds for entailing UAI and seroadaptive UAI practices. Online-delivered behavioural interventions should address insufficiency of risk-reducing practices involving UAI relative to consistent condom use and promote frequent HIV testing among MSM seeking UAI partners online. http://group.bmj.com/products/journals/instructions-for-authors/licence-forms.
authors: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA Department of Geography, McGill University, Montreal, Quebec, Canada.
authors: Joseph A
authors: JA
authors: Lewnard
authors: Department of Geography, McGill University, Montreal, Quebec, Canada.
authors: Lea
authors: L
authors: Berrang-Ford
mesh_terms: D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data*; D008297:Male; D064887:Observational Studies as Topic; D016017:Odds Ratio; D012307:Risk Factors; D012309:Risk-Taking; D012725:Sexual Behavior / Q000706:statistics & numerical data; D012747:Sexual Partners; D047568:Unsafe Sex / Q000706:statistics & numerical data*
keywords: Condoms; Gay Men; HIV; Meta-Analysis; Sexual Behaviour