Objective We evaluated the relationship among syndemic conditions (defined as a cluster of interconnected psychosocial health conditions), sexual behaviours and self-reported HIV infection in a global sample of men who have sex with men (MSM).
Methods We used generalised estimating equations logistic regression models with robust SEs to assess the relationships among cumulative number of syndemic conditions—including depression, substance use, violence, sexual stigma and homelessness—and unprotected anal intercourse (UAI) and HIV infection, while accounting for clustering within-country in a global cross-sectional survey of 3934 MSM across 151 countries.
Results We observed parallel, significant dose–response associations between the number of syndemic conditions and UAI, as well as number of syndemic conditions and HIV infection. Compared with participants without syndemics, the adjusted OR (aOR) for UAI among those with 1, 2 and 3 or more syndemic conditions were 1.44 (Bonferroni-adjusted 95% CI 1.23 to 1.68), 1.89 (1.51 to 2.36) and 2.03 (1.43 to 2.89), respectively. Compared with participants without syndemics, the aOR for HIV infection among those with 1, 2 and 3 or more syndemic conditions were 1.67 (1.24 to 2.26), 2.02 (1.44 to 2.85) and 2.35 (1.31 to 4.21), respectively.
Conclusions This analysis provides evidence of intertwining syndemics that may operate synergistically to increase HIV risk among MSM globally. To curb HIV effectively and advance the health of MSM, multiple conditions must be addressed concurrently using multi-level approaches that target both individual and structural risk factors.
- Drug Misuse
- Epidemiology (General)
- Gay Men
- Sexual Behaviour
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In low- and middle-income countries, men who have sex with men (MSM) have 19.3-fold greater odds of being infected with HIV compared with the general population.1 This high burden has been attributed to individual- and structural-level factors that may operate synergistically to increase HIV risk among MSM.2–6 The additive effect of these interconnected health conditions, known as syndemics, on HIV risk among MSM has been documented in the USA,2 ,4 ,7 yet it remains understudied in resource-limited countries.6 ,8 Despite the persistent HIV epidemic among MSM globally, most efforts to address HIV among MSM have ignored the broader spectrum of health, largely neglecting the role of other comorbidities in fuelling HIV in this population.9 We sought to address this gap in research by evaluating the association among syndemic conditions, unprotected anal intercourse (UAI) and HIV infection in a global online survey of MSM.
This is a secondary analysis of a cross-sectional online study implemented by the Global Forum on MSM & HIV from April to August, 2012; the methods of the parent study are published elsewhere.10 Participants were recruited via networks of MSM community-based organisations and MSM online websites and listservs. The parent study was exploratory in nature; no formal sample size calculations were conducted. The Research Triangle Institute International's institutional review board approved the procedures.
This analysis was limited to 3934 participants across 151 countries with complete data on outcomes and syndemics (housing status, illicit substance use, depression, sexual stigma and violence for being perceived as MSM). Syndemics of interest were limited to conditions previously associated with HIV risk among MSM.2–6 We created a composite variable for cumulative number of syndemics, which was categorised into: 0, 1, 2 and 3 or more.2 In a sensitivity analysis for UAI, we included a measure on experiences of HIV-related stigma from healthcare providers in the syndemics variable.
We fitted multivariable generalised estimating equations logistic regression models with robust SEs, accounting for clustering within country, and estimated odds for UAI and HIV infection associated with increasing numbers of syndemics, compared with those without syndemics. Models controlled for age, sexual orientation, education, racial/ethnic minority status and region. To evaluate the presence of a dose–response relationship between number of syndemics and outcomes, we tested for log-linear trend across the ordered categories of syndemics. In addition, we tested for departures from log-linear trend, assessing evidence for a quadratic pattern across categories using orthogonal contrasts, under the assumption that the categories are evenly spaced. Bonferroni-adjusted 95% CIs and p values were estimated for primary analyses models.
We also conducted subgroup analyses and assessed these dose–response relationships among MSM outside of North America and western Europe using methods detailed above. In exploratory analyses, we assessed which three syndemics reported together were associated with the greatest risk for UAI and HIV infection. We coded cross-product terms for every possible three-item combination of syndemics (eg, depression*substance use*violence) and estimated associations between these combinations and the outcomes.
The mean age of participants was 35 (range=12–90). Most participants described themselves as ‘gay’ (86%; n=3400/3934) or ‘bisexual’ (11%; n=437/3934); the majority (74%) were not from North America or western Europe (Asia=26% (n=1024/3934); Eastern Europe & Central Asia=17% (n=663/3934); Latin America=15% (n=587/3934); Sub-Saharan Africa=6% (n = 231/3934)). Complete demographics are reported elsewhere.10
In all, 46% had experienced or knew someone who had experienced violence for being perceived as MSM (n=1815/3934), and nearly a quarter used illicit substances (n=931/3934) in the prior year. Depression was reported by 17.5% (n=687/3934), while high levels of sexual stigma were reported by 8.1% (n=319/3934). HIV-related stigma from healthcare providers was experienced by 16.6% (n=654/3934). In all, 43 MSM were homeless (1.1% of 3934). Every syndemic condition was positively significantly associated with at least one other condition, confirming that these conditions are interconnected (see online supplementary table).
Overall, 67% of participants had 1 or more syndemics (n=2629/3934); 19.9% had 2 syndemics (n=783/3934) and 4.7% had 3 or more syndemics (n=185/3934) (see table 1). The overall prevalence of UAI and HIV infection was 41% (n=1613/3934) and 17.9% (n=703/3934), respectively. In bivariate analyses, two of the five syndemics were significantly associated with UAI and with HIV infection: substance use and violence against MSM (see online supplementary table).
Prevalence of UAI among those who had 0, 1, 2 and 3 or more syndemics was 33.4% (n=436/1305), 42.2% (n=701/1661), 48.7% (n=381/783) and 51.4% (n=95/185), respectively. HIV prevalence among those who had 0, 1, 2 and 3 or more syndemics was 13.4% (n=175/1305), 19.3% (n=321/1661), 21.5% (n=168/783) and 21.1% (n=39/185), respectively.
In multivariable analyses, compared with participants without syndemics, the adjusted OR (aOR) of UAI among those with 1, 2 and 3 or more syndemics were 1.44 (1.23 to 1.68), 1.89 (1.51 to 2.36) and 2.03 (1.43 to 2.89), respectively. We found evidence of a dose–response relationship with linearly increasing odds of UAI associated with greater number of syndemics (p<0.001); there was no evidence of departures from linearity (p=0.14). In subgroup analyses among MSM outside of North America and western Europe, we also observed similar dose–response associations between number of syndemics and increased odds for UAI.
Furthermore, compared with those without syndemics, the aOR of HIV infection among those with 1, 2 and 3 or more syndemics were 1.67 (1.24 to 2.26), 2.02 (1.44 to 2.85) and 2.35 (1.31 to 4.21), respectively. We also observed a dose–response relationship with evidence of linearly increasing odds of HIV infection associated with greater number of syndemics (p<0.001); there was no evidence of departures from linearity (p=0.14). In subgroup analyses among MSM outside of North America and western Europe, we also observed similar dose–response associations between number of syndemics and increased odds for HIV infection.
In exploratory analyses, we found that MSM who reported a combination of substance use, violence and sexual stigma had the greatest risk of UAI (aOR=2.39; 95% CI=1.25 to 4.58). MSM who reported a combination of depression, substance use and violence had the greatest risk of HIV infection (aOR=1.95; 95% CI 1.05 to 3.61).
In this global online study, we found evidence of intertwining syndemics that may operate synergistically to drive sexual risk behaviours and HIV transmission among MSM worldwide, including MSM outside North America and western Europe. Nearly a quarter of our sample reported two or more syndemics, underscoring the need for comprehensive integrated services to address the broad spectrum of MSM health issues. Importantly, as the number of syndemics increased, we identified a linear increase in risk for UAI and HIV infection. In this study, syndemics were interconnected and their additive effects exceeded their individual associations with UAI and HIV infection, further illustrating that these syndemic conditions have synergistic effects.
These findings suggest that there is a need to address concurrently the wide range of interrelated health and social concerns of MSM—including mental health, substance use, sexual stigma, violence and homelessness—and that doing so may strengthen HIV prevention strategies. Our overall findings and subgroup analyses for MSM outside North American and western Europe are consistent with prior studies on MSM in the USA,2 ,4 ,7 which have observed significant positive associations among sexual risk behaviour, HIV infection and number of syndemics. To our knowledge, this is the first global-scale study on MSM that has evaluated the additive effects of syndemics on risk for HIV.
Our study has limitations. This was a convenience sample; thus, findings may not necessarily be representative of all MSM globally. Recruitment via networks of MSM organisations may have led to a selection bias for MSM seeking/receiving services related to syndemics and outcomes of interest. Alternately, the online survey's internet recruitment strategies may have oversampled MSM who are more socially connected, educated and/or affluent. Thus, the prevalence of the syndemics observed and the risks associated with the outcomes of interest may also be underestimating the true prevalence and risk.
Additionally, self-reported measures may be susceptible to recall and social desirability bias. We did not conduct HIV testing to confirm self-report; thus, individuals unaware of their HIV infection could have been misclassified. We also did not collect information on the HIV status of the participants’ partners. Hence, it is not clear if those reporting UAI are at risk transmitting/acquiring HIV to/from their partners.
Finally, the study design limits our ability to infer causality (eg, HIV may lead to syndemics/vice versa). Nevertheless, the parallel dose–response relationships we observed between syndemics and the two outcomes, and the consistency of these findings with prior studies provides us with confidence in our results.2 ,4 ,7
As HIV continues to disproportionately impact MSM worldwide, it is imperative to address these multiple syndemics concurrently. Given the prevalence of syndemics among MSM, singular HIV prevention interventions will continue to be insufficient in curbing HIV among MSM. To address HIV effectively, responses must be reframed within a broader international development framework that takes into account a range of inter-connected health issues. Multi-level strategies (eg, individual-level mental health services and structural-level interventions to address homelessness, violence and sexual stigma) are needed to adequately address the range of health and social concerns facing MSM, elevate their general well-being, and ultimately reduce transmission of HIV among MSM globally.
HIV risk among MSM globally may be driven by intertwining syndemic conditions.
To curb HIV effectively and advance the health of MSM, these multiple conditions must be addressed concurrently.
Multi-level strategies are needed to adequately address the range of health and social concerns facing MSM.
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Files in this Data Supplement:
- Data supplement 1 - Online table
Handling editor Jackie A Cassell.
Contributors G-MS conceptualised the analysis, wrote the manuscript, conducted the data analysis and interpretation. TD, TP and PAW assisted in the writing of the manuscript and interpretation of data. JB, KM, SA and PH were responsible for the design of the study, assisted in the writing of the manuscript and interpretation of data. GA is the principal investigator of the study, was responsible for its design, and assisted in the writing of the manuscript and interpretation of data. All authors contributed to and approved the final draft of the manuscript.
Funding The Bill and Melinda Gates Foundation funded this study. The funder had no role in the conduct of the study or the preparation of this manuscript.
Competing interests None.
Ethics approval Research Triangle Institute International's IRB provided the IRB exemption.
Provenance and peer review Not commissioned; externally peer reviewed.