Cathy Zimmerman, Jina R, Sian Oram, Louise M. Howard, Stockl H, Brooks R, Busza J, Williams E, Strathdee Sa, Silverman Jg, Pimentel-Simbulan N, Morisky De, Mantshi Teffo-Menziwa, Urada La, and Saiqa Mullick
Siân Oram and colleagues conduct a systematic review of the evidence on the health consequences of human trafficking. They describe a limited and poor-quality evidence base, but some evidence suggests a high prevalence of violence and mental distress among women and girls trafficked for sexual exploitation, among other findings., Background There is very limited evidence on the health consequences of human trafficking. This systematic review reports on studies investigating the prevalence and risk of violence while trafficked and the prevalence and risk of physical, mental, and sexual health problems, including HIV, among trafficked people. Methods and Findings We conducted a systematic review comprising a search of Medline, PubMed, PsycINFO, EMBASE, and Web of Science, hand searches of reference lists of included articles, citation tracking, and expert recommendations. We included peer-reviewed papers reporting on the prevalence or risk of violence while trafficked and/or on the prevalence or risk of any measure of physical, mental, or sexual health among trafficked people. Two reviewers independently screened papers for eligibility and appraised the quality of included studies. The search identified 19 eligible studies, all of which reported on trafficked women and girls only and focused primarily on trafficking for sexual exploitation. The review suggests a high prevalence of violence and of mental distress among women and girls trafficked for sexual exploitation. The random effects pooled prevalence of diagnosed HIV was 31.9% (95% CI 21.3%–42.4%) in studies of women accessing post-trafficking support in India and Nepal, but the estimate was associated with high heterogeneity (I 2 = 83.7%). Infection prevalence may be related as much to prevalence rates in women's areas of origin or exploitation as to the characteristics of their experience. Findings are limited by the methodological weaknesses of primary studies and their poor comparability and generalisability. Conclusions Although limited, existing evidence suggests that trafficking for sexual exploitation is associated with violence and a range of serious health problems. Further research is needed on the health of trafficked men, individuals trafficked for other forms of exploitation, and effective health intervention approaches. Please see later in the article for the Editors' Summary, Editors' Summary Background The United Nations defines human trafficking as the recruitment and movement of individuals—most often by force, coercion or deception—for the purpose of exploitation. Essentially, human trafficking is the modern version of the slave trade and is a gross violation of human rights. People who have been trafficked may be sold on to the sex industry or forced to work in many forms of labor, including in domestic service and in the agricultural and construction industries. Given the nature of human trafficking, quantifying the scale of the problem is fraught with difficulties, but 2005 statistics estimate that 2.5 million people were in forced labor as a result of being trafficked. Why Was This Study Done? To date, the health consequences and public health implications of human trafficking have received little international attention, partly because not much is known about this area. So in this study, the researchers examined published studies in order to assimilate evidence and information on the prevalence of all forms of violence relating to people who have been trafficked and the prevalence of physical, mental, and sexual health problems, including HIV/AIDS, among this group. What Did the Researchers Do and Find? The researchers searched the published literature for suitable studies by conducting a comprehensive key word search of key databases and by contacting experts. The researchers did not exclude any type of study from their search but used stringent criteria to identify appropriate studies and then assessed the quality of identified studies by using a critical appraisal tool. Using this process, the researchers initially identified 407 papers but only 19 were suitable for their analysis, representing 16 different studies. The majority (11) of these studies were conducted in Asia (Nepal, India, Thailand, and Cambodia), and all studies focused solely on women and girls, with all but two studies examining sexual exploitation only. In their analysis of these studies, the researchers found that women and girls who had been trafficked for sexual exploitation were consistently reported to have experienced high levels of physical and sexual violence. Studies also reported a high prevalence of physical, mental, and sexual health problems among women who had been trafficked and headache, back pain, stomach pain, and memory problems were commonly reported physical health symptoms. The studies that used screening tools to identify mental distress found high levels of anxiety (48.0%–97.7%), depression (54.9%–100%), and post-traumatic stress disorder (19.5%–77.0%). Furthermore, the three studies that examined the associations between trafficking and health suggest that a longer duration of trafficking may be linked to higher levels of mental distress and increased risk of HIV infection. The few studies that examined the prevalence of HIV infection (in women accessing post-trafficking services in India and Nepal) showed a combined prevalence of 31.9%. What Do These Findings Mean? These findings, although limited, show that trafficking for sexual exploitation is associated with violence and a range of serious health problems. However, the key finding of this study is that evidence on trafficked people's experiences of violence and of physical, mental, and sexual health problems is extremely limited. There is an enormous gap in research on the health of trafficked men, trafficked children, and people who have been trafficked for labor exploitation. There is an urgent need for more and better information on the needs and experiences of people who have been trafficked, including evidence on effective interventions to mitigate the associated physical and psychological damage. Additional Information Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001224. Humantrafficking.org is a web resource for combatting human trafficking, available in a number of languages Stop the Traffick is an international movement campaigning to stop human trafficking, available in a number of languages The not for sale campaign works to abolish this form of slavery