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Abstract
Objectives Traditionally, subjects' migration status has usually been defined on the basis of their registered residency status. We attempted to redefine migration based on the duration of residency in their cities of migration and to explore more precisely the impact of migration on HIV infection risk in men who have sex with men (MSM).
Methods A multisite cross-sectional study was conducted during 2012–2013 in seven Chinese cities. Questionnaire surveys were conducted and blood was drawn to test for antibodies to HIV, syphilis and herpes simplex virus-2 (HSV-2). MSM who were unregistered local residents and had resided in their cities of migration for ≤1 or >1 year were defined as migrant MSM, or transitional MSM, respectively.
Results Compared with transitional MSM and local MSM, migrant MSM had poorer HIV knowledge and higher rates of high-risk behaviour, including earlier sexual debut, multiple sexual partners, participation in commercial sex and recreational drug use. Multivariate logistic regression analysis showed that HIV prevalence among migrant MSM was higher than local MSM (p<0.05). This relationship, however, did not hold for transitional MSM and local MSM (p>0.05). Male sex work, recreational drug use, syphilis infection and HSV-2 infection were independently associated with HIV infection among migrant MSM.
Conclusions Non-local MSM with shorter residence were at greater risk of HIV acquisition. More focus should be placed on HIV behavioural interventions targeting non-local MSM with temporary residence.
- HIV
- GAY MEN
- MIGRATION
- CHINA
- SEXUAL BEHAVIOUR
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Introduction
China has undergone a demographic shift as a result of economic prosperity and greater social freedoms. In search of work and the benefits of a modern life, the number of people migrating to cities had increased from 147 million to 253 million over the period from 2005 to 2014,1 and there is no sign of this trend slowing. Men who have sex with men (MSM) are known to be a migratory population for similar reasons,2 but may choose to migrate to cities where there is greater tolerance and peer support for homosexuality.3 Others may migrate to cities for sexual relationships after meeting a partner online or to sell sex.4
Traditionally, researchers have used registered residency status in order to define migration status. Investigations into the influence of migration status on the odds of HIV infection have produced equivocal results.5 ,6 Recent studies have suggested that migrants exhibit noticeable variation in high-risk sexual behaviours depending on their duration of residence. This is the result of interaction between migration and social contextual factors that affect behavioural characteristics associated with HIV infection risk, such as occupation and HIV-related knowledge.7 ,8 However, these studies were limited to cross-border or rural-to-urban migrants.7 ,8 Whether the same patterns are found among non-local MSM remains unclear.
On the basis of prior studies, we hypothesised that HIV was highly prevalent among non-local MSM, and that duration of residence in cities of migration would modify high-risk behaviour and HIV infection risk in MSM. Our study explores the influence of newly defined migration status on HIV infection to help identify at-risk non-local MSM, and provide targeted prevention and intervention measures to control the HIV epidemic in China.
Methods
From June 2012 to June 2013, we conducted a multicentre cross-sectional study in seven Chinese cities including Shenyang, Changsha, Kunming, Ji'nan, Nanjing, Shanghai and Zhengzhou. Participants were recruited, through internet, venue-based sampling and peer referrals. Participants were eligible to participate if they were male, ≥18 years of age, able and willing to provide informed consent, and reported having anal sex with other men in the last 12 months.
Participants completed an anonymous questionnaire concerning sociodemographics, HIV-related knowledge and sexual behaviours. All interviews were held in a private room. And after pretest counselling, venous blood of participants was drawn by trained nurses to test for antibodies to HIV, syphilis and herpes simplex virus-2 (HSV-2).
Demographically, migrants who had resided in their cities of migration for >1 year could be regarded as permanent migration.9 Therefore, ‘migrant’ MSM were defined, for the purposes of our study, as those not claiming city residency who had resided in their cities of migration for ≤1 year; ‘transitional’ MSM were defined as those not having registered as local residents who had resided there for >1 year.
χ2 trend test and χ2 test were calculated to evaluate the proportions between all three above-mentioned groups of MSM. We also estimated factors associated with HIV infection among all MSM and three MSM subgroups using univariate and multivariate logistic regression analyses.
Results
Altogether 4496 eligible MSM were recruited in our study, among whom 750 (16.7%) were defined as migrant, 1961 (43.6%) as transitional and 1785 (39.7%) as local MSM.
Among migrant MSM, transitional MSM and local MSM, a decreasing trend could be observed in regard to proportion of age ≤25 years (32.0% vs 31.3% vs 25.8%); educational level <college (64.0% vs 50.8% vs 35.8%); being unmarried (76.0% vs 70.1% vs 66.7%); HIV knowledge scores (67.5% vs 54.8% vs 50.3%); age <20 years of sexual debut (68.3% vs 60.5% vs 54.5%); >2 male sexual partners (46.0% vs 41.4% vs 32.7%); buying sex from males (11.2% vs 7.2% vs 4.1%); selling sex to males (16.0% vs 8.1% vs 2.7%); and recreational drug use in the last 6 months (31.9% vs 29.4% vs 25.7%) (each p for trend <0.05).
Unadjusted HIV (10.4% vs 9.9% vs 9.6%) and syphilis (8.8% vs 8.3% vs 8.5%) prevalence in migrant MSM and HSV-2 prevalence in local MSM (11.2% vs 11.9% vs 13.1%) were higher than in the other two subgroups, though this difference was not statistically significant (p>0.05).
Results of univariate and multivariate analyses for factors associated with HIV infection among all MSM groups and for the three MSM subgroups are separately shown in table 1. Compared with local MSM, migrant MSM had a higher odds of HIV infection (p<0.05) while transitional MSM did not (p>0.05). Surprisingly, migrant MSM who had a history of selling sex to males were more likely to get infected with HIV, while transitional MSM were less likely to get infected (each p<0.05).
Univariate and multivariate‡ logistic regression analyses of factors associated with HIV infection among total MSM, migrant MSM, transitional MSM and local MSM
Discussion
The results of our study point to the existence of a potentially important subgroup of the non-local MSM population in Chinese cities with a distinctive sexual risk profile. The subgroup of MSM who had been resident in their cities of migration for ≤1 year were found to have characteristics that distinguished them, from the established local MSM population, and from other non-local MSM. Our study sought both to describe this group, and at the same time to argue for a change in the official classification that currently conceals its existence.
Our case for a revision of how migration status is classified rests upon results from the multivariate analysis of our data. When, for the purposes of our analysis, we employed a classification that distinguished ‘migrant’ MSM (resident for ≤1 year) from ‘transitional’ MSM (non-local but resident for >1 year), it was found that, in migrant non-local MSM, the odds of HIV infection were higher than they were in the local MSM population, whereas, in transitional non-local MSM, they were lower. However, when we employed a definition of migration status that ignored the distinction between ‘migrant’ and ‘transitional’ (as does the current official classification), we discovered no significant difference in HIV prevalence as between non-local and local MSM (10% vs 9.6%, p=0.662; adjusted OR, 1.1 (0.9–1.4), p=0.232). This suggests to us that the official definition of immigration status is concealing important distinctions between subgroups of non-local MSM in respect to HIV risk profile, and could be leading to a corresponding misdirection of public health interventions.
When we assume the proposed threefold classification of ‘migrant’, ‘transitional’ and ‘local’ MSM status, a picture emerges of the relation between migration status and risk factors for HIV that is rather different from what we find in earlier studies.7 ,8 The latter have suggested that risk factors for HIV in the MSM population increase with duration of residence; our own work points to the existence of an important subgroup—‘migrant’ MSM—that earlier research based on the official classification of migration status might have led us to overlook. These ‘migrant’ MSM are shown by our results to display a number of characteristics that are associated with exposure to particular sexual risk, such as young age, low levels of education and unmarried status.3 Future research should further investigate the diverse risk factors affecting the ‘migrant’, as opposed to the ‘transitional’, MSM population.
One particularly unexpected finding from our analysis is that the association of HIV infection with selling sex should be stronger by comparison with local MSM in the case of migrant MSM, and weaker by comparison with local MSM in the case of transitional MSM. The weaker association in the case of transitional MSM is surprising in view of the findings of prior studies that have shown the higher risks incurred by MSM in general through selling sex because of number of sexual partners and recreational drug use.10 Maybe this intriguing finding points to the effect of differences of HIV knowledge as between more recent and more long-standing participants in the sexual market place.4 However, it is important to note relatively high levels of participation by both migrant and transitional commercial sex workers in programmes specifically designed to target both groups, and especially migrant workers.
In addition, this study corroborates the findings of earlier studies in regard to the independent correlation of HIV infection among total MSM and all three MSM subgroups with various other factors including recreational drug use, syphilis infection and HSV-2 infection.5 ,10 The public health services need, therefore, to enhance their understanding of recreational drug use among MSM, and further develop interventions to target high-risk sexual behaviours and encourage engagement with care among that population.
Our study had the following limitations. First, the relatively small size of our sample of migrant MSM limited our ability to detect some correlates with HIV infection found among the other two subgroups. Second, our redefinition of migration status could appear somewhat arbitrary, and it is unclear whether the same patterns would have emerged, had we fixed the cut-off for the migrant subgroup at 3 or 6 months rather than a year. Third, due to the nature of a cross-sectional study, we failed to make causal inference and calculate HIV incidence. Finally, proportions of high-risk behaviour among our subjects may be underestimated owing to social desirability bias. Strengths in our study included large sample size, stringent implementation of uniform study protocol, and the redefinition of migrant MSM status so as to cause their true features were concealed.
Conclusion
We have made the case for a revised classification of the non-local MSM that distinguished the categories of ‘migrant’ (≤1 year) and ‘transitional’ (>1 year). By employing this classification, we have found an association not reflected in earlier studies between more recent residence on the part of urban MSM (≤1 year) and high risk of HIV because of various demographic and behavioural factors, including prostitution. Future research should address itself to the causes of the high differential risk of the ‘migrant’ MSM population in order to guide the development of programmes aimed at this high-risk group.
Acknowledgments
The authors would also like to thank all the MSM subjects who attended this study and all the staffs at the Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, the First Affiliated Hospital, China Medical University, Yunnan CDC, Jiangsu CDC, He'nan CDC, Shanghai CDC, Hu'nan CDC and Shandong CDC for their contribution to this study. The authors would like to thank Scottie Bussell, MD, MPH, for his help with editing the manuscript.
Supplementary materials
Abstract in Chinese
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- Abstract in Chinese - Online abstract
Footnotes
Y-qY and J-jX contributed equally.
Handling editor Jackie A Cassell
Contributors Y-qY, J-jX and HS conceived and designed the experiments. Y-qY, J-jX, Q-hH, H-JY, ZW, LL, M-hZ, XC and J-hF performed the study and experiments. Y-qY, J-jX and Q-hH analysed the data. Y-jJ and W-qG contributed reagents/materials/analysis tools. Y-qY, J-jX, Y-lQ and HS wrote and revised the manuscript. All authors read and approved the final manuscript.
Funding The study was funded by the Mega-Projects of National Science Research for the 12th Five-Year Plan (2012ZX10001-006), China-Gates Foundation Cooperation Programme (2012), Liaoning Educational Department Research Project (LZ2014038) and Research project of the first hospital of CMU (FSFH1512).
Competing interests None declared.
Patient consent Obtained.
Ethics approval The study protocol and content approval were obtained from the Institutional Review Board of the First Affiliated Hospital of China Medical University (No. [2011]36). Written informed consent for each participant was collected before the initiation of the survey.
Provenance and peer review Not commissioned; externally peer reviewed.