Telling truth from Ys: an evaluation of whether the accuracy of self-reported semen exposure assessed by a semen Y-chromosome biomarker predicts pregnancy in a longitudinal cohort study of pregnancy

The Value of Assessing Self-Reported and Biological Indicators of Outcomes in Evaluating HIV Programs

PURPOSE OF REVIEW

In this manuscript, we present recent findings concerning concordance and discrepancy between biological measures and self-reports of these three outcomes of HIV programs: HIV status, adherence to antiretroviral medications (ARVs) and use of and adherence to pre-exposure prophylaxis medication (PrEP), and condom use/unprotected sex.

RECENT FINDINGS

Recent studies suggest that three successive rapid HIV tests (for those whose first test in positive) might be reasonably inexpensive and valid biological data to collect to combine with self-reports of HIV status, dried blood spots sufficiently affordable to combine with self-reports of adherence to ARVs and use of or adherence to PrEP, and that the discrepancy between self-reports of condom use and biomarkers of unprotected sex may be relatively small in high-income countries. Additional work on assessment of incorrect condom usage and breakage, standardized self-report measures of condom use, and more private data collection methodologies in low-income settings might reduce the recent observed discrepancies even further. Concordance between self-reports of HIV and biomarkers indicating HIV positive status has varied considerably, with much lower rates in low-income countries, where the stigma of HIV is still very high. Recommendation is for combining self-report data with the results of three successive rapid tests for those testing positive. For adherence, again agreement between self-reports and a variety of more objective and/or biological measures is only moderate. Dried blood spots (DBS) may be sufficiently inexpensive in low-resource settings that this may be the best biological method to combine with self-reports. In publications over the last 8 years, the discrepancy between self-reports of condom use and biomarkers for unprotected sex may be even lower than 20% after controlling for other features of the study, particularly in high-income countries. Our results suggest that more careful assessment of incorrect condom use and breakage as reasons other than intentional misreporting should be investigated more carefully and that more private data collection methods such as audio, computer-assisted self-interviewing (ACASI) might be employed more often in low-resource settings to reduce this discrepancy in those settings further. In addition, further analysis of the discrepancy between self-reports of condom use and biomarkers should be conducted of published studies using the correct calculation methods to be more certain of these findings.

Reproductive coercion sometimes works: evaluating whether young African-American women who experience reproductive coercion or birth control sabotage are more likely to become pregnant

Men engaging in reproductive coercion may coerce, force, or deceive female partners into pregnancy. This study evaluates whether the 3-month incidence of pregnancy is higher among women reporting reproductive coercion than similar women reporting no reproductive coercion. We tested this hypothesis in longitudinal data from a sample of African-American women ages 18–24 recruited from community settings in Atlanta, Georgia, US, in 2012–2014 (n = 560). Participants were surveyed at baseline, 3 months, 6 months, 9 months, and 12 months. To reduce selection bias, we used full matching on 22 baseline variables related to demographics, economic power, risky alcohol use, and gender-based power inequality. We used logistic regression in the matched sample with outcome pregnancy 3 months later, controlling for baseline fertility intentions (n = 482, n = 458, n = 452 at respectively 3, 6, 9 months). At 3 months, 15% of women reported reproductive coercion. At 6 months, 11.3% of women reporting coercion were pregnant vs. 4.6% of matched women reporting no coercion (p = 0.06). Women reporting coercion had 3 times the odds of pregnancy as matched women reporting no coercion (AOR 2.95, 95% CI (1.16, 6.98), p = 0.02). Among women pregnant after coercion, only 15% wanted to be pregnant then or sooner. Women reporting reproductive coercion are at greater risk of unwanted or mistimed pregnancies, and the semen exposure that caused these pregnancies could also transmit STI/HIV. Clinicians should screen patients for reproductive coercion; consider using semen exposure biomarkers such as PSA or Yc-PCR to identify condom sabotage or stealthing; and refer women experiencing reproductive coercion to supportive services.

PrEP Use Among Female Sex Workers: No Evidence for Risk Compensation

Supplemental Digital Content is Available in the Text.

Little is known about risk compensation among female sex workers (FSW) on HIV pre-exposure prophylaxis (PrEP), and self-report of sexual behaviors is subject to bias.

Brief report: Assessing the risk of reporting bias in a RCT for adolescent mothers

INTRODUCTION

Most adolescent sexual and reproductive health studies rely solely upon self-report surveys to assess key variables such as pregnancy and sexually transmitted infections (STIs). The current study investigated the risk of reporting bias that may result from using such surveys to measure outcomes in randomized controlled trials (RCTs).

METHODS

As part of an RCT of a multicomponent intervention to delay repeat pregnancy among adolescent mothers, we compared survey data on repeat pregnancy with birth records from a state's vital statistics system. The survey assessed contraceptive use, pregnancy status, and future pregnancy intentions. The sample consisted of American adolescents ages 18 and 19 years who were at least 28 weeks pregnant or less than nine weeks postpartum.

RESULTS

For 14 of 331 study participants (4 percent), we found a birth record in the vital statistics system for a mother who reported not having gotten pregnant on the survey. We found no evidence of underreporting for the other survey respondents. The rate of underreporting was similar for the intervention and control groups.

CONCLUSIONS

A low rate of underreporting for repeat pregnancy in adolescent mothers was found in the present sample.

Biological Validation of Self-Reported Unprotected Sex and Comparison of Underreporting Over Two Different Recall Periods Among Female Sex Workers in Benin

Background

Self-reported unprotected sex validity is questionable and is thought to decline with longer recall periods. We used biomarkers of semen to validate self-reported unprotected sex and to compare underreporting of unprotected sex between 2 recall periods among female sex workers (FSW).

Methods

At baseline of an early antiretroviral therapy and pre-exposure prophylaxis demonstration study conducted among FSW in Cotonou, Benin, unprotected sex was assessed with retrospective questionnaires, and with vaginal detection of prostate-specific antigen (PSA) and Y-chromosomal deoxyribonucleic acid (Yc-DNA). Underreporting in the last 2 or 14 days was defined as having reported no unprotected sex in the recall period while testing positive for PSA or Yc-DNA, respectively. Log-binomial regression was used to compare underreporting over the 2 recall periods.

Results

Unprotected sex prevalence among 334 participants was 25.8% (50.3%) according to self-report in the last 2 (or 14) days, 32.0% according to PSA, and 44.3% according to Yc-DNA. The proportion of participants underreporting unprotected sex was similar when considering the last 2 (18.9%) or 14 days (21.0%; proportion ratio = 0.90; 95% confidence interval, 0.72–1.13). Among the 107 participants who tested positive for PSA, 19 (17.8%) tested negative for Yc-DNA.

Conclusions

Underreporting of unprotected sex was high among FSW but did not seem to be influenced by the recall period length. Reasons for discrepancies between PSA and Yc-DNA detection, where women tested positive for PSA but negative for Yc-DNA, should be further investigated.

Y Chromosome DNA in Women's Vaginal Samples as a Biomarker of Recent Vaginal Sex and Condom Use With Male Partners in the HPV Infection and Transmission Among Couples Through Heterosexual Activity Cohort Study

BACKGROUND

Y chromosome DNA from male epithelial and sperm cells was detected in vaginal samples after unprotected sex in experimental studies. We assessed the strength of this association in an observational setting to examine the utility of Y chromosome DNA as a biomarker of recent sexual behaviors in epidemiological studies.

METHODS

The HPV (human papillomavirus) Infection and Transmission Among Couples Through Heterosexual Activity cohort study enrolled 502 women attending a university or college in Montréal, Canada, and their male partners from 2005 to 2010. Participants completed self-administered questionnaires. We used real-time polymerase chain reaction to test women's baseline vaginal samples for Y chromosome DNA and assessed which sexual behaviors were independent predictors of Y chromosome DNA positivity and quantity with logistic and negative binomial regression.

RESULTS

Y chromosome DNA positivity decreased from 77% in women in partnerships reporting vaginal sex 0 to 1 day ago to 13% in women in partnerships reporting last vaginal sex of 15 or more days ago (adjusted odds ratio, 0.09; 95% confidence interval, 0.02-0.36). The mean proportion of exfoliated vaginal sample cells with Y chromosome DNA was much lower for women who reported always using condoms (0.01%) than for women who reported never using condoms (2.07%) (adjusted ratio, 26.8; 95% confidence interval, 8.9-80.5). No association was found with reported oral/digital sex frequency or concurrency of partnerships.

CONCLUSIONS

Y chromosome DNA quantity is strongly associated with days since last vaginal sex and lack of condom use in observational settings. Y chromosome DNA quantity may prove useful as a correlate of recent vaginal sex in observational studies lacking data on sexual behavior, such as surveillance studies of human papillomavirus infection prevalence.

Prevalence and risk factors associated with STIs among women initiating contraceptive implants in Kingston, Jamaica

BACKGROUND

There is limited information on rates of STIs in Jamaica due to syndromic management and limited aetiological surveillance. We examined the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) and characteristics associated with STIs among sexually active women who participated in a randomised trial of a progestin implant initiation in Jamaica (the Sino-Implant Study (SIS)).

METHODS

SIS was a randomised trial conducted in Kingston, Jamaica, from 2012 to 2014 to evaluate whether initiation of the Sino-Implant (II) led to more unprotected sex among women ages 18-44 years. Data collected included self-reported demographic, sexual behaviour information; and vaginal swabs collected at baseline, 1-month and 3-month follow-up visits for a biomarker of recent semen exposure (prostate-specific antigen (PSA)) and for STIs. We examined associations between STIs and PSA, demographics, sexual behaviour and insertion of an implant, with a repeated-measures analysis using generalised estimating equations (SAS Institute, V.9.3).

RESULTS

Remnant vaginal swabs from 254 of 414 study participants were tested for STIs. At baseline, 29% of participants tested for STIs (n=247) had laboratory-confirmed CT, 5% NG, 23% TV and 45% any STI. In a repeated-measures analysis adjusted for study arm (immediate vs delayed implant insertion), those with PSA detected did not have an increased prevalence of any STI (prevalence ratio (PR)=1.04 (95% CI 0.89 to 1.21)), whereas prevalence decreased for each 1-year increase in age (PR=0.98 (95% CI 0.97 to 0.99)). Immediate implant insertion was not associated with increases in any STI in subsequent visits (PR=1.09 (95% CI 0.94 to 1.27)).

CONCLUSIONS

Although the prevalence of laboratory-confirmed STIs was high, the immediate initiation of a contraceptive implant was not associated with higher STI prevalence rates over 3 months.

TRIAL REGISTRATION NUMBER

NCT01684358.

Recent Biomarker-Confirmed Unprotected Vaginal Sex, But Not Self-reported Unprotected Sex, Is Associated With Recurrent Bacterial Vaginosis

BACKGROUND

Self-reported unprotected vaginal sex seems to increase risk of bacterial vaginosis (BV). However, the validity of self-reports is questionable, given their inconsistency with more objective measures of recent semen exposure such as detection of prostate-specific antigen (PSA). We examined whether recent unprotected sex, as measured both by PSA detection on vaginal swabs and by self-report, was associated with increased BV recurrence.

METHODS

We analyzed randomized trial data from nonpregnant, BV-positive adult women recruited from a sexually transmitted disease clinic. Participants received BV therapy at enrollment and were scheduled to return after 4, 12, and 24 weeks. Bacterial vaginosis (by Nugent score) and PSA were measured at each visit. We used Cox proportional hazards models to examine the association between PSA positivity and recurrent BV. We also evaluated associations between self-reported unprotected sex (ever/never since the last visit and in the last 48 hours, analyzed separately) and recurrent BV.

RESULTS

Prostate-specific antigen and BV results were available for 96 women who contributed 226 follow-up visits. Prostate-specific antigen positivity was associated with increased BV recurrence (adjusted hazard ratio [aHR], 2.32; 95% confidence interval [CI], 1.28-4.21). In contrast, we observed no significant increase in BV recurrence among women self-reporting unprotected sex since the last visit (aHR, 1.63; 95% CI, 0.77-3.43) or in the last 48 hours (aHR, 1.28; 95% CI, 0.70-2.36).

CONCLUSIONS

Estimates from earlier studies linking self-reported unprotected sex and BV may be biased by misclassification. Biomarkers can improve measurement of unprotected sex, a critical exposure variable in sexual health research.

Semen says: assessing the accuracy of adolescents' self-reported sexual abstinence using a semen Y-chromosome biomarker

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.

Risky behaviors and helmet use among young adolescent motorcyclists in Southern Thailand

BACKGROUND

In Thailand, road traffic injuries are the leading cause of death for youth ages 15-19 years, with 80% of the injuries and deaths from motorcycle accidents.

OBJECTIVES

To determine the prevalence of child and young adolescent motorcyclists in Hat Yai municipality and their risk behaviors.

METHOD

A cross-sectional study was conducted between June 2011 and March 2012 in which 2,471 students, ages 8 to 18 years, were recruited from 9 primary and secondary schools in Hat Yai municipality. The questionnaire included questions on being a motorcycle rider or passenger, risky behaviors, and helmet use while riding.

RESULTS

Of the total, 1,573 (63.7%) were riders and 898 (36.3%) were pillion passengers. The majority of the riders younger than 15 years rode their motorcycle mainly only in narrow streets for a short trip. Only 30% of the riders wore a helmet every time they rode a motorcycle. About 10% of the participants riding or a passenger on a motorcycle had consumed alcohol at least once before riding their motorcycle. Multiple logistic regression analysis found that motorcycle injuries were significantly associated with speeds greater than 60 km/h, not wearing a helmet while riding, and alcohol consumption before riding (odds ratios 1.63, 1.59, and 3.09, respectively).

CONCLUSION

Nearly two thirds of young adolescents in Hat Yai municipality were motorcycle riders. These young adolescents were at risk of traffic injuries because more than 50% of them had ridden at high speed or not worn a helmet while riding, and some of them had consumed alcohol before riding.