Objective Researchers often assess condom use only among participants who report recent sexual behaviour, excluding participants who report no recent vaginal sex or who did not answer questions about their sexual behaviour, but self-reported sexual behaviour may be inaccurate. This study uses a semen Y-chromosome biomarker to assess semen exposure among participants who reported sexual abstinence or did not report their sexual behaviour.
Methods This prospective cohort study uses data from 715 sexually active African–American female adolescents in Atlanta, surveyed at baseline, 6 months and 12 months. Participants completed a 40 min interview and were tested for semen Y-chromosome with PCR from a self-administered vaginal swab. We predicted Y-chromosome test results from self-reported sexual behaviour using within-subject panel regression.
Results Among the participants who reported abstinence from vaginal sex in the past 14 days, 9.4% tested positive for semen Y-chromosome. Among item non-respondents, 6.3% tested positive for semen Y-chromosome. Women who reported abstinence and engaged in item non-response regarding their sexual behaviour had respectively 62% and 78% lower odds of testing positive for Y-chromosome (OR 0.38 (0.21 to 0.67), OR 0.22 (0.12 to 0.40)), controlling for smoking, survey wave and non-coital sexual behaviours reported during abstinence.
Conclusions Adolescents who report sexual abstinence under-report semen exposure. Research should validate self-reported sexual behaviour with biomarkers. Adolescents who engage in item non-response regarding vaginal sex test positive for semen Y-chromosome at similar rates, which supports the practice of grouping non-respondents with adolescents reporting abstinence in statistical analysis.
Trial registration number NCT00633906.
- SEXUAL BEHAVIOUR
- HETEROSEXUAL BEHAVIOUR
- EPIDEMIOLOGY (GENERAL)
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Handling editor Jackie A Cassell
Contributors JER conceived the study, analysed the data and wrote the manuscript. RJD, GMW and ER designed the survey, collected the data. JMZ devised the PCR procedure. All authors revised the manuscript and approved the version to be published.
Funding This research was funded by the School of Public Health at SUNY Downstate Medical Center, Brooklyn, New York, USA. The data collection was funded by R01 MH061210 from the Center for Mental Health Research on AIDS, National Institute of Mental Health, Bethesda, Maryland, USA (RJD and GMW).
Competing interests None declared.
Ethics approval Emory University IRB (327-99).
Provenance and peer review Not commissioned; externally peer reviewed.
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