1. Jessica McDermott Sales, PhD
The Validity of Adolescents’ Self-Reported Behavior Results from a sexual risk-reduction trial with African American female adolescents
Eve Rose, MSPH
Ralph J. DiClemente, PhD
Gina M. Wingood, ScD, MPH
Jessica McDermott Sales, PhD
Teaniese P. Latham, MPH
Richard A. Crosby, PhD
Jonathan Zenilman, MD
James Hardin, PhD

2. Background: Self-Reported Behavior
Cornerstone of reproductive & sexual health research
Self-report of sexual behavior prone to biases
Self reported behavior data is the cornerstone of reproductive and sexual health research; the foundation of how we collect data
However, self-report of sexual behaviors prone to biases, including:
Recall biases (encoding, distortion, retrieval, reconstruction)
Social desirability bias
other

3. Counteracting Biases Shorter recall periods
Cues (i.e. events, activities)
ACASI - audio computer
assisted self-interviewing
Biomarkers to validate self-report data
Over the last several decades, we’ve made improvements in how we format and frame sexual behavior question to enhances the validity of self-reported sexual behavior
We counteract these biases using:
Shorter recall periods
Cues (important events, activities, calendar)
ACASI (audio computer assisted self-interviewing) which also helps combat literacy barriers
Bio-markers to validate self-reported data (will look at this more in next slide)

4. Biomarkers of Sexual Activity
Incident STDs
PSA - Prostate Specific Antigen
YcPCR - Y chromosome polymerase chain reaction assay
Incident STDs
PROS - Objective & quantifiable
CONS
requires high risk sample with high STD prevalence & incidence therefore if they’re not having sex w/partners w/STDs then you’re more likely to get a FALSE NEGATIVE
Large sample
Must follow sample for a long period of time
PSA
Can be detected in vaginal fluid for hours after exposure to semen
Been used as a measure of condom failure
YcPCR (will qualify this in next slide)

5. History of YcPCR Y chromosome polymerase chain reaction
Swab-based assay
More sensitive than PSA
Detects Yc in vagina 2 weeks post unprotected coitus
Non-disease bio-marker of unprotected sex
YcPCR
Swab-based assay
More sensitive than PSA
Detects y chromosome in vagina 2 weeks post coitus
as opposed to PSA which is only detectable for hours after semen exposure
ADVANTAGE – non-disease biomarker of unprotected sex, therefore
Don’t have to have a sample with high STD rates

6. Methods: Study Sample Eligibility criteria 1,558 screened 874 eligible
African American female
Age 15 to 21 years
Sexual activity in past 60 days
Not married
Not pregnant or attempting to become pregnant
1,558 screened
874 eligible
715 enrolled; represents an
82% participation rate

7. Methods: Data Collection
Biospecimen
STD screen
YcPCR
ACASI: Self-reported condom use
“How many times did you have vaginal sex in the past 14 days prior to assessment?”
“How many of these times did you use a condom?”
14 day recall period matches YcPCR “detection window”
Bio-specimen
2 self-collected swabs
STD screen (gonorrhea, chlamydia, trich)
Z-probe for YcPCR
ACASI – audio computer assisted self-interview
Self-reported sexual behaviors asking:
# of times you had vaginal in past 14 days (defined vaginal sex as “a guy puts his penis in vagina”
# of times used a condom in these sex acts
(used a 14 day recall period to match the YcPCR detection period)

8. Methods: Data Analysis
Condom use:
# of acts w/condom # of vaginal sex acts in past 14 days
Therefore:
Consistent condom use (100%)
vs.
Inconsistent condom use (<100%)
Used a proportional measure of condom use by dividing the total # of vaginal sex acts in the past 14 days by the # of times a condom was used in the sex acts.
Then we dichotomized condom use by
Consistent use (100% condom use)
&
Inconsistent (less than 100% condom use)

9. Results N=484 reporting sex in past 14 days with a valid YcPCR
Mean age = 17.9 years (SD = 1.7)
Majority currently enrolled in school,
25% graduated or received GED
89% report a current boyfriend
33% report casual sex partner(s)

10. Concordance of self-reported consistent condom use & YcPCR assay
Results
Consistent condom use in past 14 days (n=186)
34% (n=63)
positive on YcPCR assay
Discordant results
Concordance of self-reported consistent condom use & YcPCR assay
34%
66%
Of the 484 participants with a valid YcPCR assay and reporting sexual activity in the past 14 days,
186 reported consistent condom use in the past 14 days
Of these, 34% (n=63) has a positive YcPCR assay (DISCORDANT RESULTS)
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11. Frequency of sex in past 14 days*
Factors associated with reporting consistent condom use & having a positive YcPCR assay
Age
Prior STD history*
Frequency of sex in past 14 days*
Having sex while high on drugs/alcohol or while partner was high on drugs/alcohol
# of partners in past 14 days
Physical, emotional, or sexual abuse history
_____________________________________________________________________________________________________________________________
* p<.05
Conducted a Pearson correlation for all risk factors except for abuse history which was done with a chi-square
At the .05 level, and 2 variables were significant for girls who reported consistent condom use and had a positive YcPCR
Prior STD history (positive relationship)
Frequency of sex in the past 14 days (positive relationship)
Since these were significant on the bivariate level, we then conducted a multivariate logistic regression

12. Multivariate Logistic Regression
Model predicting YcPCR results
Prior STD history
Frequency of sex
Among consistent condom users, those with a self-reported prior STD were 2.4 times (95%CI= ; p=) more likely to have a positive YcPCR assay (discordant results)
Conducted multivariate logistic regression w/prior STD history & frequency of sex
Prior STD history was significant, therefore
Of consistent condom uses, girls w/ a prior STD history were 2.4 times more likely to have a positive YcPCR or discordant results.

13. Discordance between self-report & objective biological marker
YcPCR specificity 92%
Misreporting
Poor recall
Social desirability bias
Condom Use Error
Not measured in the current sample
Can run as high as 38% in this population
What we were interested in was the discordance between self-reported sexual behavior (consistent condom use) and an objective measure of unprotected sex (YcPCR)
YcPCR assay has a specificity of over 90% when condoms are properly used
The 2 explanations that stood out to us were issues of misreporting and condom use error
Misreporting
Poor recall of their sexual activity in the past 14 days, and/or
Social desirability bias
girls in our sample are recruited from 3 metropolitan STD clinics
we conduct our assessments at the same clinics. Girls receive STD services, including STD testing and counseling at these clinics
Based on the setting we’re in, girls could be misreporting condom use based on what they think they should say, even if it’s contrary to their actual behaviors
Condom use error
Condom error includes: breaking, leaking, slipping off, re-use, late application, early removal
This study did not have a measure of condom use error
Previous research with this population reports condom uses error from 36 to 38%
The good news is that we’ve added a measure of condom error to a behavior maintenance study we’re doing now with this population
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14. Limitations YcPCR Limited generalizability
Valid for detecting Yc within a 2-week period
Can only be conducted with females
Detectable levels can come from other sources
Limited generalizability
African American females
In metropolitan area
YcPCR
Valid for looking at a 2 week window of semen exposure
Can only be conducted with females
Detectable levels can come from other sources, including oral sex and digital penetration. HOWEVER – can use a cut-off value.
YcPCR is measured in nanograms and one solution is to establish a cut-off value of nanograms that can account for the presence of y chromosome in the vagina from sources other than penile penetration of the vagina
Limited generalizability

15. Conclusions Optimize self-report YcPCR
ACASI
Timeline Follow-back Method
Shorter recall windows
YcPCR
Easy to administer
Can supplement and validate self-report of sexual activity
Triangulated approach provides comprehensive picture of STD & HIV risk for females
Additional studies by our research team are currently underway.