title: Biomarker validation of reports of recent sexual activity: results of a randomized controlled study in Zimbabwe.
abstract: Challenges in the accurate measurement of sexual behavior in human immunodeficiency virus (HIV) prevention research are well documented and have prompted discussion about whether valid assessments are possible. Audio computer-assisted self-interviewing (ACASI) may increase the validity of self-reported behavioral data. In 2006-2007, Zimbabwean women participated in a randomized, cross-sectional study that compared self-reports of recent vaginal sex and condom use collected through ACASI or face-to-face interviewing (FTFI) with a validated objective biomarker of recent semen exposure (prostate-specific antigen (PSA) levels). Of 910 study participants, 196 (21.5%) tested positive for PSA, an indication of semen exposure during the previous 2 days. Of these 196 participants, 23 (11.7%) reported no sex in the previous 2 days, with no difference in reported sexual activity between interview modes (12.5% ACASI vs. 10.9% FTFI; Fisher's exact test: P = 0.72). In addition, 71 PSA-positive participants (36.2%) reported condom-protected vaginal sex only; their reports also indicated no difference between interview modes (33.7% ACASI vs. 39.1% FTFI; P = 0.26). Only 52% of PSA-positive participants reported unprotected sex during the previous 2 days. Self-report was a poor predictor of recent sexual activity and condom use in this study, regardless of interview mode, providing evidence that such data should be interpreted cautiously.
authors.affiliation: Women's Global Health Imperative, RTI International, San Francisco, CA 94104, USA. aminnis@rti.org
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Minnis
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Steiner
authors.forename: Maria F
authors.initials: MF
authors.lastname: Gallo
authors.forename: Lee
authors.initials: L
authors.lastname: Warner
authors.forename: Marcia M
authors.initials: MM
authors.lastname: Hobbs
authors.forename: Ariane
authors.initials: A
authors.lastname: van der Straten
authors.forename: Tsungai
authors.initials: T
authors.lastname: Chipato
authors.forename: Maurizio
authors.initials: M
authors.lastname: Macaluso
authors.forename: Nancy S
authors.initials: NS
authors.lastname: Padian
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D017280:Condoms; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D006801:Humans; D011939:Mental Recall; D008875:Middle Aged; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000032:analysis*; D015203:Reproducibility of Results; D021841:Safe Sex / Q000502:physiology; D012725:Sexual Behavior / Q000502:physiology*; D014621:Vagina / Q000737:chemistry*; D015030:Zimbabwe
chemical_list: D015415:Biomarkers; D017430:Prostate-Specific Antigen