Women who have been trafficked for sexual exploitation experience violence and poor physical and mental health but there is little evidence available about the health consequences experienced by trafficked children, men or people trafficked for other forms of exploitation according to a study by UK researchers published in this week's PLoS Medicine.

Although —defined by the UN as the recruitment and movement of individuals, most often by force, coercion or deception, for the purpose of exploitation—affects millions of men, women and children around the world, so far, the and public health implications of human trafficking have received little international attention.

So a team of researchers from London, UK, led by Siân Oram from King's College London's Institute of Psychiatry, in collaboration with the London School of Hygiene and Tropical , examined all relevant published studies in order to gather evidence and information on the frequency of all forms of violence relating to people who have been trafficked and the frequency of physical, mental, and sexual health problems.

The authors found studies consistently reported that women and girls who had been trafficked for experienced high levels of physical and sexual violence. In addition, they experienced high levels of physical, sexual, and problems: headache, back pain, stomach pain and memory problems were common as were anxiety, depression and post-traumatic stress disorder. Furthermore, the authors found that a longer duration of exploitation may be linked to higher levels of mental distress.

The authors say: "findings from studies to date indicate that trafficking is associated with serious health problems and suggest that trafficked people are likely to require a coordinated response by health care providers and other support services."

However, one of the key findings 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.

The authors conclude: "Further research is needed on the health of trafficked men, individuals trafficked for other forms of exploitation, and effective health intervention approaches."

They add: "As there is no sign that human trafficking is abating, we need more and better information on trafficked people's needs and experiences, including evidence on interventions to mitigate the physical and psychological damage associated with this global crime."

More information: Oram S, Stöckl H, Busza J, Howard LM, Zimmerman C (2012) Prevalence and Risk of Violence and the Physical, Mental, and Sexual Health Problems Associated with Human Trafficking: Systematic Review. PLoS Med 9(5): e1001224. doi:10.1371/journal.pmed.1001224

Journal information: PLoS Medicine