What's Impulsivity Got to Do with It? Exploring the Association Between Delay Discounting and Risky Sexual Behavior in Men Who Have Sex with Men Público

Jones, Jeb Stuart (2016)

Permanent URL: https://etd.library.emory.edu/concern/etds/qv33rx39r?locale=es


Men who have sex with men (MSM) experience the highest number of new diagnoses of human immunodeficiency virus (HIV) each year in the United States despite comprising approximately 2% of the population. Additional interventions are needed to increase condom use to reduce HIV transmission in this key group. Delay discounting is a measure of impulsivity that might be related to sexual risk-taking. Delay discounting has the potential to serve as an indicator of risk and as a target for behavioral HIV risk-reduction interventions. We conducted three studies to illustrate the possible role of delay discounting in HIV risk among MSM.

In the first study, we examined the association between monetary and sexual discounting in an online sample of MSM in the United States. Monetary discounting suffers from less social desirability bias compared to measures of sexual delay discounting and, therefore, might provide a more reliable proxy measure of sexual risk. Among 1,012 MSM we did not observe an association between sexual and monetary discounting.

In the second study, we used the same online sample of MSM to examine the association between sexual and monetary discounting and condomless anal intercourse (CAI) in the past 12 months. We did not observe an association between monetary discounting and CAI; however, we did observe a robust association between sexual discounting and CAI. This suggests that men who discount condom-protected sex are more likely to engage in sex without a condom and that monetary discounting would not be a good proxy measure for sexual risk-taking.

In the third study, we used an agent-based model to estimate the potential impact of a delay-discounting intervention on population-level incidence of HIV. Depending on the assumptions that were used in the model, we show that 4-14% of infections could be averted over a ten-year period.

These findings suggest that sexual, but not monetary, delay discounting is associated with sexual risk-taking among MSM and that an intervention targeting delay discounting could result in meaningful decreases in HIV incidence. Future cohort studies should assess the longitudinal relationship between delay discounting and CAI and explore strate gies for discounting-based risk-reduction interventions.

Table of Contents

Table of Contents

Chapter 1: Background and Significance 1 Chapter 2: Assessing the concordance between monetary and sexual delay discounting in an online study of men who have sex with men 18 Chapter 3: Assessing the association between monetary and sexual delay discounting and risky sexual behavior in an online sample of men who have sex with men 40 Chapter 4: Estimating the Potential Impact of a Delay Discounting Intervention to Reduce HIV Transmission Using Agent-Based Modeling 65 Chapter 5: Conclusions and Public Health Implications 86 References 97 Appendix A 120 Appendix B. Components of a network model of a delay discounting intervention for MSM 170 Appendix C. Key parameters in a network model of a delay discounting intervention for MSM 171 List of Tables Table 1.1. Adjusted prevalence ratios (PR) and confidence intervals for condomless anal intercourse with any and multiple partners in the past 12 months 10 Table 2.1. Demographic characteristics of the study population overall and dichotomized by sexual discounting status 29 Table 2.2. Reasons that no standardized AUC value was obtained for each SDT condition 30 Table 2.3. Mean, median, minimum, and maximum values for the log-transformed k and AUC for each SDT condition. AUCs are presented for the fully study population, including participants who did not discount condom-protected sex, and for the subset of participants who did discount condom-protected sex 31 Table 2.4. Change in mean lnk associated with increases in sexual discounting for each condition of the SDT for categorized and rank-transformed AUC 33 Table 2.5. Chi square tests examining the concordance between no vs. any delay discounting on the MCQ and SDT 34 Table 3.1. Sample demographics, relationship characteristics, and HIV testing history overall and stratified by CAI in the past 12 months 52 Table 3.2. Distribution of delay discounting variables 53 Table 3.3. Adjusted prevalence differences for CAI and monetary delay discounting 54 Table 3.4. Adjusted prevalence differences for CAI and each condition of the SDT by category, stratified by age group 56 Table 3.5. Adjusted prevalence differences for CAI and any discounting on the SDT, stratified by age group 58 Table 3.6. Adjusted prevalence differences for CAI and each condition of the SDT by category, stratified by current PrEP use 60 Table 4.1. Assumptions for four different model conditions testing the impact of which partner determines condom-use and whether delay discounters are eligible to be assigned to always use a condom with non-main partners 71 Table 4.2. Coverage and effectiveness scenarios considered in a stochastic model of an intervention for delay discounting of condom-protected sex among US MSM 71 Table 4.3. Prevalence, incidence per 100 person-years, percent of infections averted, and number of infections averted with 95% credibility intervals for each coverage and effectiveness scenario for Conditions 1 and 2 74 List of Figures Figure 1.1. Differences in delayed value of $1000 for different values of the monetary delay discounting parameter k 6 Figure 4.1. Percent of infections averted by Effectiveness and Prevailing Condom Use Probability, 20% Intervention Coverage in conditions where some discounters always used condoms 75 Figure 4.2. Percent of infections averted by effectiveness and prevailing condom use probability assuming 20% efficacy in conditions where no discounters always used condoms 78

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