Men who have sex with men (MSM) in exchange for money (male sex workers; MSW) are at increased risk of HIV infection, with a significantly higher HIV prevalence (35% vs. 20%)1 compared with nonsex worker MSM in the United States. Recent research from major cities across the United States documented that 13% of HIV-infected MSW were unaware of their infection,2 whereas another study found this proportion to be as high as 42%.3 Men who engage in sex work report behavioral risk factors for HIV, including higher numbers of sexual partners, more frequent condomless anal sex with men and women,2,4 and drug use.2–6
Among MSWs, contextual differences create heterogeneity of HIV risk as well.4,5,7 Specifically, men who primarily find clients and conduct sex work on the street may be at higher risk for HIV infection compared with MSWs who find clients online, even while MSWs who find clients online report higher risk behaviors with nontransactional partners.5,7 Although reasons for these patterns of risk are not well understood, limited research suggests that they may be associated with differing structural and psychosocial factors between street- and internet-based sex workers, including lower levels of education, higher unemployment, higher rates of unstable housing, and higher rates of drug use.2,4–7 Additional research to further describe heterogeneity of HIV risk among MSWs is warranted.
In addition to distinct behavioral patterns, relationships between MSWs and their clients and intimate partners, and the sexual and drug networks that MSWs occupy, may be important to understanding patterns of HIV risk among MSWs.7,8 Social network studies can elucidate the impact of relational structures beyond individual-level behaviors and other risk factors,9,10 and may be particularly helpful when HIV is not randomly distributed in a network of people.10–13 Specifically, network studies may identify concurrency (ie, distinct partnerships that overlap in time), homophily (ie, when individuals who share a particular attribute are more likely to share a network), and multiplexity [ie, the likelihood that individuals' different types of networks (eg, drug and sex) overlap], and examine whether differences in these relationship structures impact HIV transmission risk.
Despite being frequently hypothesized as important drivers of HIV transmission, and a growing body of research on the role of sexual networks in HIV transmission among MSM,9 research is very limited on network characteristics of MSWs.7 Studies have found that MSWs are more likely than MSM who do not engage in sex work to have a recent sexual partner of unknown HIV serostatus and a partner with a history of injection drug use.2,6–8 However, no previous study, to our knowledge, has used a network design to simultaneously examine the sexual and drug use networks of MSWs. To this end, we conducted an egocentric network interview assessment with MSWs to characterize these network characteristics and examine their potential associations with patterns of condom use with their male clients.
Participants and Procedures
This analysis uses data from a cohort study of 100 MSW conducted between 2014 and 2016 in greater Boston, MA and Providence, RI. Participants were recruited using passive methods, including flyering, paid advertisements and referrals, and active methods, including partnerships with community-based organizations who serve this population, phone calls, messages, and emails to MSWs found on websites where men advertise or solicit sex. Inclusion criteria included being 18 years or older, having a male sex assigned at birth, identifying as male, and having had anal or oral sex with 3 or more men in exchange for money in the month before enrollment.
Data for this analysis comes from a comprehensive, computer-assisted quantitative assessment, which consisted of 3 sections: (1) completed by the participant alone, the assessment's audio-computer assisted self-interview (ACASI) section included measures on highly stigmatized and/or sensitive topics (eg, sexual risk behavior, substance and alcohol use); (2) administered by the interviewer, the second section included less sensitive measures (eg, demographics, healthcare access, and utilization); and (3) completed with the interviewer, a social network inventory assessed composition of participants' social, sexual, and drug use networks. Participants were informed that they could use initials, single letters or nicknames to refer to individuals in their networks, and there was no cap on the number of individuals in their networks that could be named. Each study visit took approximately 1.5 hours to complete and were conducted at Fenway Health (Boston) or Project Weber (Providence). All procedures were approved by the institutional review board at Fenway Health.
For this analysis, men who did not complete the network assessment were excluded (n = 5), resulting in an analytic sample of 95 MSWs.
Age, race/ethnicity [dichotomized as non-Hispanic white vs. person of color (black/African American; Hispanic/Latino; Asian; American Indian/Alaskan Native; Native Hawaiian or other Pacific Islander; and other another minority race/ethnicity)] and sexual orientation were reported. In addition, participants reported their highest level of educational attainment and whether they currently had any formal employment outside of sex work. They also indicated whether they were currently single, in a monogamous relationship, or a non-monogamous relationship.
Participants indicated whether they currently had any health insurance coverage, whether they had been unstably housed in the past 6 months, and whether they had been detained or incarcerated (for at least one night) in the past 6 months.
Depression was assessed using 20-item Center of Epidemiologic Studies Depression Scale (CESD).14 The items were summed and then dichotomized at a standard cutoff score of 16 or higher, indicating clinically significant depressive symptoms in the past 7 days. Hazardous drinking was assessed using the 10-item Alcohol Use Disorders Identification Test (AUDIT).15 Scale items were summed and dichotomized based on a standard cut of score of 8 or higher, which is suggestive of hazardous drinking in the past 6 months. Recent drug use was assessed by asking participants whether they had used any of the following drugs in the past 6 months: poppers, marijuana, methamphetamine, crack/cocaine, prescription benzodiazepines, prescription opioids, hallucinogens (eg, lysergic acid diethylamide, Phencyclidine), ecstasy, gamma hydroxybutyrate, ketamine, heroin, or prescription erectile enhancers. Recent injection drug use was assessed by asking participants whether they had injected any drugs to get high in the past 6 months. Substance use during sex work was assessed by responses to whether they had used alcohol or any drugs during or within 2 hours before engaging in sex work.
Sex Work-Related Measures
Sex work venue was assessed by asking participants to indicate where they primarily met clients—street, internet, or both—which was dichotomized into “street only” vs. “internet only/mixed.” Motivations for starting sex work (money, drugs, pleasure, and coercion) were reported, and participants could select any that applied—as such, the categories are not mutually exclusive. Participants also reported whether or not sex work was their sole source of income, whether or not they disclosed their sex work to family or friends, and the frequency with which they engaged in sex work (dichotomized into at least weekly vs. less than weekly). Finally, participants indicated whether they enjoyed sex work always/usually, sometimes, or rarely/never.
Person-Level Measure of Sexual Behaviors With Male Clients
Participants reported the total number of condomless anal sex acts (insertive or receptive) they engaged in with all male clients in the past month.
Dyad-Level Measure of Sexual Behaviors With Male Clients
In the network inventory (see below), participants reported whether they had engaged in anal sex with the listed male client and the frequency with which they used condoms with that listed male client (categorized as never using condoms, using condoms at the start of the relationship, but no longer using them, using condoms every now and then, or always using condoms). This variable was then dichotomized into always using condoms vs. inconsistent condom use or condom nonuse (herein referred to as “inconsistent condom use”).
Rapid HIV testing was conducted using the OraQuick ADVANCE rapid HIV test. A blood sample was collected via finger-prick or blood draw (if the participant chooses to receive the optional STI testing). If the participant had a reactive test result, confirmatory testing was done immediately in coordination with the Massachusetts Department of Public Health. Pretest and post-test counseling for HIV prevention followed standard of care, including information about HIV and STI transmission routes and prevention methods.
Social Network Characteristics
In the network inventory, participants reported on the age, race/ethnicity, and perceived HIV status of their past-month male exchange partners, as well as whether they also used drugs with their partners. Based on these inventory items, we created measures of age homophily (ie, whether the partner's age was within 1 year of the participant's, whether the partner was 2 or more years younger than the participant, and whether the partner was 2 or more years older than the participant), racial/ethnic homophily (ie, whether the participant and their partner were the same racial/ethnic group), and HIV status homophily (ie, whether the participant perceived their partner to be the same HIV status). Levels of racial/ethnic homophily in these networks were calculated using an assortativity coefficient based on 6 categories of race/ethnicity (non-Hispanic white, non-Hispanic black/African American, Hispanic/Latino, Asian, American Indian/Alaskan Native, Other) rather than the binary variable used in all other analyses. In addition, consistent with the literature,16–18 multiplexity is indicated whether the sexual partner is also in participant's drug use network.
All statistical analyses were conducted in R Studio (Version 1.1.456). First, descriptive statistics were calculated to summarize study variables. Second, bivariable analyses (eg, one-way analysis of variance for continuous variables and χ2 test of independence or Fisher exact tests for categorical variables) were conducted to examine differences in demographic, behavioral, and social characteristics by sex work venue.
Separate multivariable analyses were conducted to examine: (1) correlates of inconsistent condom use during engagement in anal sex with male clients, and (2) the total number of condomless anal sex acts with male clients. Correlates of inconsistent condom use during engagement in anal sex with male clients were identified using hierarchical logistic regression, adjusting for the nesting of reported dyads of participants and their male clients within individual participants. This regression modeling approach allowed us to identify the associations of both individual (eg, a participant's HIV status) and dyadic (eg, concordance between a participant's HIV status and the HIV status of their partner) characteristics with these outcomes. The results of these analyses are expressed as odds ratios (ORs). Correlates of the total number of condomless anal sex acts with male clients were identified using modified Poisson regression to account for overdispersion in the outcome. The results of this analysis are expressed as incidence rate ratios (IRRs).
All initial multivariable models included key individual-level characteristics (eg, participant age, race/ethnicity, HIV status, motives for initiating sex work) and network-level characteristics (eg, homophily; multiplexity in participants' sexual and drug use ties). Models were reduced after examining variance inflation factors (VIFs) to identify multicollinearity. Variables with high VIFs were removed through an iterative process, where the variables with the highest VIFs were removed until all VIFs were less than 2.19
Number of Partners
Among 95 MSWs, participants reported a total of 503 male clients during the sexual network assessment, ranging from 1 to 22 male clients per participant in the past month, with a mean of 5.3 clients (SD: 3.4) per participant (Fig. 1).
Characteristics of MSW Participants
The characteristics of the MSW participants are displayed in Table 1. Forty-seven participants (49.5%) reported only meeting clients on the street, 25 (26.3%) reported only meeting clients on the internet and 23 (24.2%) reported using a mix of venues to meet their clients. A higher proportion of participants who met their clients on the street identified as straight or heterosexual (19.6%) compared with those who met their clients on the Internet or through a mix of venues (4.2%) (P = 0.026). In addition, participants who met their clients on the street had attained lower levels of education (P = 0.021): 23.4% had not completed high school (compared to 6.3% of those who met their clients on the Internet or through a mix of venues). Recent experiences of unstable housing were also more common among participants who met their clients on the street (55.3% vs. 27.0%; P = 0.010). A higher proportion of participants who met their clients on the street indicated that their motivations for initiating sex work were related to drugs (55.3%) compared with participants who met their clients on the internet or through a mix of venues (31.3%, P = 0.031).
Characteristics of Male Clients
Nearly 60% (n = 293) of clients were 40 or older and 72% (n = 356) were White, non-Hispanic. Nearly 16% (n = 80) were unemployed. MSW participants were in a relationship for 6 months or less with approximately 40% (n = 186) of clients. MSW participants discussed HIV status with 47% (n = 236) of clients and reported that 5% of clients (n = 25) were HIV-positive. Overall, MSWs reported that 29.4% (n = 148) of clients used heroin, crack, cocaine, and/or methamphetamines in the preceding month, and 50.5% (n = 48) had at least one client who used heroin, crack, cocaine, and/or methamphetamine in the past month.
Sexual and Drug Use Network Characteristics
Nearly 80% (n = 385) of clients were presumed by the MSW participant to have concurrent sex partners, yet MSW participants discussed condom use outside of this relationship with only 7% of clients (n = 37). On average, 30.4% of the clients were also drug use partners (SD: 34.8), ranging from 0% to 100%. MSW participants showed a significant tendency toward having older clients (r(493) = 0.19, P < 0.001). Conversely, in race, a medium positive assortativity coefficient (AC = 0.23) suggests that many MSW participants reported sexual partnerships with clients of the same race.
Inconsistent Condom Use During Anal Sex With Male Clients
Participants reported engagement in anal sex with 74.1% of male clients in the past month. Among dyads where anal sex was reported, participants reported inconsistent condom use with 53.0% of clients in the past month. Correlates of inconsistent condom use during anal sex with male clients are shown in Table 2. In multivariable models, inconsistent condom use was more common in relationships with perceived HIV status homophily; that is, where their partner was assumed to be of the same HIV status [OR: 1.25; 95% confidence interval (CI): 1.07 to 1.46] and sexual and drug network multiplexity (OR: 1.19; 95% CI: 1.09 to 1.30). Inconsistent condom use during anal sex was less common within relationships where the client is older than the MSW participant (OR: 0.83; 95% CI: 0.74 to 0.93).
Total Number of Condomless Anal Sex Acts With Male Clients
On average, participants engaged in condomless anal sex with male clients 2.2 times per month (SD: 4.6). Correlates of the total number of condomless anal sex acts with male clients are shown in Table 3. Higher number of condomless anal sex acts were reported by older participants (IRR: 1.04; 95% CI: 1.01 to 1.07) and participants who reported reasons for initiating sex work related to drug use (IRR: 2.71; 95% CI: 1.49 to 4.93). In addition, participants with high multiplexity, that is a higher number of male clients who were also members of their drug use network, had higher likelihood of more condomless anal sex acts with male clients (IRR: 1.35; 95% CI: 1.19 to 1.54).
Although small qualitative studies5 and samples of MSM who report some past engagement in transactional sex2,4 have elucidated potential unique risk factors for HIV, to the best of our knowledge, this is the first study to describe the sexual and drug use networks of men who actively engage in regular sex work with other men in the United States. In this sample of men in the Northeast U.S., we found that men who primarily conducted sex work on the street (vs. online) were more likely to report factors that have been shown to be associated with HIV in other populations, including lower educational attainment, more unstable housing, and higher depressive symptoms. This is consistent with qualitative findings reported by Mimiaga et al,5 which described distinct characteristics and risks for street-based vs. online MSWs. In addition, we found that men who met clients on the street were more likely to identify as straight or bisexual (rather than gay) and more likely to have become involved in sex work due to drugs. Notably, sex work venue was not associated with differences in sexual risk behaviors in multivariable models, with high levels of risk taking in both groups. Taken together, our findings suggest that programs and interventions to reduce risk for HIV for MSWs are needed regardless of sex work venue; however, these interventions may need to account for substantial heterogeneity of motivations, experiences, and structural and psychosocial risk factors among MSWs.
In this sample, several network characteristics were associated with condomless anal sex with male clients, even after adjusting for individual-level characteristics. Previous studies with other at-risk populations have found that age discordance, particularly where the partner is substantially older, is associated with increased HIV risk.20–23 These studies have hypothesized that this is due to unequal power dynamics in which the older partner holds a disproportionate amount of power in the relationship, and as such, the younger partner may not have the agency to demand condom use.23,24 However, in contrast, we found that age discordance within an MSW-client dyad was associated with reduced odds of inconsistent condom use. In other words, in dyads where the MSW and the client were the same age, inconsistent condom use was more common. A study of young MSM found a similar pattern,24 and hypothesized that individuals may perceive older men as being more likely to be HIV-positive and therefore are more likely to use condoms during these encounters. Importantly, this perceived difference in risk by age of client may not be accurate, and as such interventions must ensure that MSWs are given the tools to effectively negotiate condom use with clients during anal sex, or use other HIV prevention modalities that do not require client approval, such as pre-exposure prophylaxis, or PrEP.
Conversely, presumed HIV status homophily was associated with increased odds of inconsistent condom use with male clients. Although this is consistent with the literature on serosorting,25 and may be a reasonable harm reduction behavior for HIV,26 in this sample, MSW participants only spoke with less than half of their of clients about their HIV status. As such, this strategy, which relies on accurate knowledge of the partner's serostatus,27 may be inadequate protection against HIV transmission.28,29 Moreover, given that approximately 80% of clients were presumed by the MSW participant to have concurrent sex partners and discussions about condom use with other sex partners was rare (7%), it is imperative that interventions equip MSWs to both have discussions about HIV status and to use condoms and/or PrEP for HIV prevention in these high-risk partnerships.
Drug use among MSW participants in this sample was high: ∼90% overall and 71% during sex work. Moreover, MSWs estimated that nearly a third of their clients used heroin, crack, cocaine, and/or methamphetamines. Given this, it is not surprising that MSW participants also used drugs with nearly one-third of clients, and this multiplexity between sex and drug use networks was associated with condomless anal sex. This finding is consistent with previous research demonstrating that sexual/drug use multiplexity is a significant risk factor for condomless sex among young MSM20 and people who inject drugs.30 In addition to fostering higher risk sex (ie, less condom use in the context of drug use, exchange sex for drugs),31,32 overlap in sexual and drug networks may hinder individual behavior change,31 and may result in additional pathways for HIV transmission (eg, via syringe/needle or equipment sharing).31,33 Programs that assess multiplex relationships may improve targeting for HIV prevention activities, including behavioral and biomedical interventions.
These findings should be understood in the context of the study's limitations. The data relied on self-report by the MSW participant, and their report of their clients' demographics and behaviors. As such, there may be misclassification in both individual and network characteristics. Moreover, due to the small numbers of HIV-positive participants and partners, we were unable to examine network-level risk factors for HIV prevalence. In addition, this was a convenience sample and may not represent the broader population of MSWs. Similarly, although the inclusion of only high-risk men who have engaged in recent and ongoing exchange sex limits potential confounding by level of risk, it also limits the generalizability of our findings to other subgroups, including men who may only occasionally sell sex or those who only exchange sex for drugs. Fourth, the small sample size may have limited our ability to detect true associations and increased the risk of type II error. Finally, our sample comes from Boston, MA and Providence, RI and may not be generalizable to other geographic regions.
Notwithstanding these limitations, this is the first study, to our knowledge, to describe sexual and drug network characteristics of MSWs. Although more studies are needed to confirm these associations, the results of this study suggest that networks are important drivers of sexual risk for MSWs, and as such, future studies should consider network characteristics when exploring HIV and other sexually transmitted infection transmission. Moreover, future studies could use sociometric network data collection and analysis to further elucidate how networks of MSWs are connected, and to obtain data directly from clients. Finally, these data suggest that behavioral and structural interventions should consider the role of networks when addressing HIV/STI risk among MSWs, and drug treatment programs should ensure that they are inclusive of gay, bisexual, and other MSM.
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