title: Population size, HIV, and behavior among MSM in Luanda, Angola: challenges and findings in the first ever HIV and syphilis biological and behavioral survey.
abstract: OBJECTIVE
  To conduct the first population size estimation and biological and behavioral surveillance survey among men who have sex with men (MSM) in Angola.
  
  
  METHODS
  Population size estimation with multiplier method and a cross-sectional study using respondent-driven sampling.
  
  
  METHODS
  Luanda Province, Angola. Study was conducted in a large hospital.
  
  
  METHODS
  Seven hundred ninety-two self-identified MSM accepted a unique object for population size estimation. Three hundred fifty-one MSM were recruited with respondent-driven sampling for biological and behavioral surveillance survey.
  
  
  METHODS
  Interviews and testing for HIV and syphilis were conducted on-site. Analysis used Respondent-Driven Sampling Analysis Tool and STATA 11.0. Univariate, bivariate, and multivariate analyses examined factors associated with HIV and unprotected sex. Six imputation strategies were used for missing data for those refusing to test for HIV.
  
  
  RESULTS
  A population size of 6236 MSM was estimated. Twenty-seven of 351 individuals were tested positive. Adjusted HIV prevalence was 3.7% (8.7% crude). With imputation, HIV seroprevalence was estimated between 3.8% [95% confidence interval (CI): 1.6 to 6.5] and 10.5% (95% CI: 5.6 to 15.3). Being older than 25 (odds ratio = 10.8, 95% CI: 3.5 to 32.8) and having suffered episodes of homophobia (odds ratio = 12.7, 95% CI: 3.2 to 49.6) significantly increased the chance of HIV seropositivity.
  
  
  CONCLUSIONS
  Risk behaviors are widely reported, but HIV seroprevalence is lower than expected. The difference between crude and adjusted values was mostly due to treatment of missing values in Respondent-Driven Sampling Analysis Tool. Solutions are proposed in this article. Although concerns were raised about feasibility and adverse outcomes for MSM, the study was successfully and rapidly completed with no adverse effects.
authors.affiliation: *Department of Global Community Health and Behavioral Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA; †Department of Community Health, Federal University of Ceará, Fortaleza, Brazil; ‡Department of Epidemiological Surveillance, Ministry of Health, Fortaleza, Fortaleza, Brazil; §Centers for Disease Control and Prevention, Atlanta, Georgia, USA; ‖Oswaldo Cruz Foundation, Rio de Janeiro, Brazil; ¶Director, National Institute of the Fight against AIDS, Luanda, Angola.
authors.forename: Carl
authors.initials: C
authors.lastname: Kendall
authors.forename: Ligia Regina Franco Sansigolo
authors.initials: LR
authors.lastname: Kerr
authors.forename: Rosa Maria Salani
authors.initials: RM
authors.lastname: Mota
authors.forename: Socorro
authors.initials: S
authors.lastname: Cavalcante
authors.forename: Raimunda Hermelinda Maia
authors.initials: RH
authors.lastname: Macena
authors.forename: Sanny
authors.initials: S
authors.lastname: Chen
authors.forename: Nicholas
authors.initials: N
authors.lastname: Gaffga
authors.forename: Edgar
authors.initials: E
authors.lastname: Monterosso
authors.forename: Fransisco I
authors.initials: FI
authors.lastname: Bastos
authors.forename: Dulcelina
authors.initials: D
authors.lastname: Serrano
mesh_terms: D002947:Cities / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology*; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D011156:Population Density; D021841:Safe Sex; D013587:Syphilis / Q000453:epidemiology*