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Member Research & Reports

Member Research & Reports

Maryland Links Bias in Self-Reported Condom Use with Syphilis among Mid-age Female Sex Workers in China

Dr. Hongjie Liu, University of Maryland School of Public Health professor, is the lead author in a new study published in AIDS and Behavior, which examines the association between over-reporting condom use via self-reports with syphilis in mid-age female sex workers (FSWs) in China. The study found that FSWs who had active or prevalent syphilis were more likely to over report condom use.


[Photo: Dr. Hongjie Liu]

The study, published online in December 2015, is part of an on-going three-site study in China examining condom use in FSWs. The three cities were chosen from different geographic locations in China to represent variation in HIV and STI epidemic levels. Dr. Liu, an epidemiology professor, and his colleagues focused on FSWs over the age of 35, based on previous research that indicates cases of HIV and other STIs are increasing most rapidly among adults over 50 years of age, many of which reported a history of commercial sex with mid-age FSWs

To determine over-reporting of condom use, the researchers interviewed 1,245 FSWs from the three cities and conducted prostate-specific antigen (PSA) tests to confirm recent unprotected sexual activity. They also collected blood specimens for syphilis testing.

Researchers found that the proportion of over-reported condom use with all sex partners (clients, husbands, or boyfriends) was 26–46 percent across the three study sites. Over-reported condom use was defined as reporting no unprotected sex for the past 24 hours but testing positive for PSA, a biomarker that indicates exposure to semen. FSWs who were prevalent or active syphilis cases were more likely to over-report condom use than FSWs who were not prevalent or active cases. Additionally, FSWs who had a more favorable view of condoms were more likely to over-report condom use.

Self-reported condom use has long been a tool used by researchers to measure protected sex. However, over-reporting of condom use may occur when sex workers misunderstand questions, have problems remembering past condom use, make inaccurate estimations, or try to perceive the researchers’ expectations and reduce the degree of stigma.

The results from this study suggest that self-reported condom use may no longer be a valid approach for measuring levels of protected sex in behavioral studies and interventional trials. In contrast, the PSA test is relatively inexpensive, rapid, and more accurate for assessing condom use in the past 24-48 hours.

“Given the inconsistencies resulting from self-reporting,” said Dr. Liu, “now is the time to start using biological assays such as the PSA test to measure actual condom use.”

Dr. Liu, an expert in social and behavioral aspects of HIV/AIDS and research methodology, has led and participated in over a dozen studies HIV-related studies in China. This study is the first to document the potential influence of prevalent and incident syphilis on self-reported condom use.