title: Is Group Sex a Higher-Risk Setting for HIV and Other Sexually Transmitted Infections Compared With Dyadic Sex Among Men Who Have Sex With Men?
abstract: BACKGROUND
  Group sex has been suggested as a potential high-risk setting for HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM). We investigated whether group sex is associated with lower condom use during anal sex and higher proportions of STIs compared with dyadic sex among HIV-negative MSM between 2009 and 2012.
  
  
  METHODS
  Cross-sectional data from 7 data waves of the Amsterdam Cohort Studies were used. The sample consisted of 465 MSM who either reported both group and dyadic sex (at n = 706 visits) or dyadic sex only (at n = 1339 visits) in the preceding 6 months. Logistic regression with generalized estimating equations was used to investigate the association between sexual setting (group vs. dyadic sex), condomless anal sex, and STI.
  
  
  RESULTS
  Group sex was reported at 35% (706/2045) of visits. Condomless sex was more often reported during dyadic than group sex (odds ratio, 3.64 95% confidence interval, 2.57-5.16). Men who had group sex were more likely diagnosed as having gonorrhea compared with men with dyadic sex (odds ratio, 1.71; 95% confidence interval, 1.08-2.97), but this effect was not retained in the multivariate model.
  
  
  CONCLUSIONS
  Results demonstrate within-person differences in sexual behavior during group and dyadic sex among MSM. Men were more likely to use condoms during group sex than during dyadic sex. Thus, for some, group sex may not necessarily be risky for HIV infection compared with dyadic sex. However, group sex may be a higher-risk setting for acquiring STIs other than HIV, such as gonorrhea. Group sex encounters should be recognized as distinct sexual settings with specific risk characteristics that need to be addressed accordingly.
authors.affiliation: From the *Department of Infectious Diseases Research and Prevention, Public Health Service Amsterdam, Amsterdam, the Netherlands; †Department of Infectious Diseases, Tropical Medicine and AIDS, CINIMA, Academic Medical Center, Amsterdam, the Netherlands; and ‡HIV Center for Clinical and Behavioral Studies, Department of Psychiatry, New York State Psychiatric Institute and Columbia University, New York, NY.
authors.forename: Wijnand
authors.initials: W
authors.lastname: van den Boom
authors.forename: Udi
authors.initials: U
authors.lastname: Davidovich
authors.forename: José
authors.initials: J
authors.lastname: Heuker
authors.forename: Femke
authors.initials: F
authors.lastname: Lambers
authors.forename: Maria
authors.initials: M
authors.lastname: Prins
authors.forename: Theo
authors.initials: T
authors.lastname: Sandfort
authors.forename: Ineke G
authors.initials: IG
authors.lastname: Stolte
mesh_terms: D000328:Adult; D015331:Cohort Studies; D017280:Condoms / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D006069:Gonorrhea / Q000517:prevention & control / Q000635:transmission*; D015658:HIV Infections / Q000517:prevention & control / Q000635:transmission*; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D012306:Risk; D021841:Safe Sex; D012725:Sexual Behavior; D012747:Sexual Partners; D012749:Sexually Transmitted Diseases / Q000517:prevention & control / Q000635:transmission*