title: The comparability of men who have sex with men recruited from venue-time-space sampling and facebook: a cohort study.
abstract: BACKGROUND
  Recruiting valid samples of men who have sex with men (MSM) is a key component of the US human immunodeficiency virus (HIV) surveillance and of research studies seeking to improve HIV prevention for MSM. Social media, such as Facebook, may present an opportunity to reach broad samples of MSM, but the extent to which those samples are comparable with men recruited from venue-based, time-space sampling (VBTS) is unknown.
  
  
  OBJECTIVE
  The objective of this study was to assess the comparability of MSM recruited via VBTS and Facebook.
  
  
  METHODS
  HIV-negative and HIV-positive black and white MSM were recruited from June 2010 to December 2012 using VBTS and Facebook in Atlanta, GA. We compared the self-reported venue attendance, demographic characteristics, sexual and risk behaviors, history of HIV-testing, and HIV and sexually transmitted infection (STI) prevalence between Facebook- and VTBS-recruited MSM overall and by race. Multivariate logistic and negative binomial models estimated age/race adjusted ratios. The Kaplan-Meier method was used to assess 24-month retention.
  
  
  RESULTS
  We recruited 803 MSM, of whom 110 (34/110, 30.9% black MSM, 76/110, 69.1% white MSM) were recruited via Facebook and 693 (420/693, 60.6% black MSM, 273/693, 39.4% white MSM) were recruited through VTBS. Facebook recruits had high rates of venue attendance in the previous month (26/34, 77% among black and 71/76, 93% among white MSM; between-race P=.01). MSM recruited on Facebook were generally older, with significant age differences among black MSM (P=.02), but not white MSM (P=.14). In adjusted multivariate models, VBTS-recruited MSM had fewer total partners (risk ratio [RR]=0.78, 95% CI 0.64-0.95; P=.01) and unprotected anal intercourse (UAI) partners (RR=0.54, 95% CI 0.40-0.72; P<.001) in the previous 12 months. No significant differences were observed in HIV testing or HIV/STI prevalence. Retention to the 24-month visit varied from 81% for black and 70% for white MSM recruited via Facebook, to 77% for black and 78% for white MSM recruited at venues. There was no statistically significant differences in retention between the four groups (log-rank P=.64).
  
  
  CONCLUSIONS
  VBTS and Facebook recruitment methods yielded similar samples of MSM in terms of HIV-testing patterns, and prevalence of HIV/STI, with no differences in study retention. Most Facebook-recruited men also attended venues where VTBS recruitment was conducted. Surveillance and research studies may recruit via Facebook with little evidence of bias, relative to VBTS.
authors.affiliation: Rollins School of Public Health, Department of Epidemiology, Emory University, Atlanta, GA, United States. alfonso.claudio.hernandez@emory.edu.
authors.forename: Alfonso C
authors.identifier: https://orcid.org/0000-0002-3971-337X
authors.initials: AC
authors.lastname: Hernandez-Romieu
authors.forename: Patrick S
authors.identifier: https://orcid.org/0000-0002-7728-0587
authors.initials: PS
authors.lastname: Sullivan
authors.forename: Travis H
authors.identifier: https://orcid.org/0000-0003-1133-4762
authors.initials: TH
authors.lastname: Sanchez
authors.forename: Colleen F
authors.identifier: https://orcid.org/0000-0001-5611-0119
authors.initials: CF
authors.lastname: Kelley
authors.forename: John L
authors.identifier: https://orcid.org/0000-0003-4357-2298
authors.initials: JL
authors.lastname: Peterson
authors.forename: Carlos
authors.identifier: https://orcid.org/0000-0002-0153-3517
authors.initials: C
authors.lastname: Del Rio
authors.forename: Laura F
authors.identifier: https://orcid.org/0000-0002-7723-0715
authors.initials: LF
authors.lastname: Salazar
authors.forename: Paula M
authors.identifier: https://orcid.org/0000-0002-3078-9124
authors.initials: PM
authors.lastname: Frew
authors.forename: Eli S
authors.identifier: https://orcid.org/0000-0002-1695-8075
authors.initials: ES
authors.lastname: Rosenberg
keywords: Facebook; men who have sex with men, MSM; online MSM; social media recruitment of MSM; venue-based time sampling