Nearly a third of women throughout the world are victims of violence perpetrated by their intimate partners (IPV), according to results of a global meta-analysis that synthesized data from more than 140 studies carried out globally.

The results of the meta-analysis indicate that as of 2010, 30.0% of women 15 years of age or older have, at some point in their lives, been the target of physical and/or sexual violence carried out by an intimate partner.

When violence perpetrated by nonpartners is added to the mix, even more women are at risk — about 35%, according to the study findings.

The meta-analysis was published online June 20 as a Policy Forum in Science. It was a joint venture of the World Health Organization, the London School of Hygiene and Tropical Medicine, and the South African Medical Research Council.

The results of the meta-analysis are also included in a new World Health Organization report coupled with guidelines for prevention of both partner and nonpartner violence.

The World Health Organization report calls violence against women "a global health problem of epidemic proportions" and emphasizes that all healthcare workers, regardless of setting, need to be trained to recognize and appropriately respond to women at risk.

The report points out that certain healthcare settings (eg, antenatal clinics and HIV screening clinics) offer good opportunities to spot problems and intervene.

However, to be effective in such situations, the recommendations say, certain minimum standards need to be in place. Those include that:

providers need to be trained on how to ask about violence,

standard operating procedures need to be in place,

consultations need to take place in private settings,

confidentiality needs to be guaranteed,

referral arrangements need to established and maintained, and

providers need to be properly equipped to handle the physical and mental consequences of sexual assault.

A decade ago, at a global conference, the international community acknowledged that IPV was a serious problem that needed to be addressed. Since then, there has been a growing consensus among researchers on how to best document physical and/or sexual partner violence.

Those methods usually involve one-on-one interviews, conducted in private, in which women are asked whether they have been the victims of specific types of violence.

"As a result of this consensus and a greater global commitment to addressing violence against women, over the past decade, there has been a rapid expansion in the number of population studies examining IPV prevalence," K. M. Devries, PhD, from the Gender Violence and Health Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom, and colleagues write in the Science article.

Even so, those studies vary considerably in their methods, and that has made their findings difficult to interpret.

Aiming to better understand the magnitude of the problem, the researchers analyzed data from 141 studies carried out in 81 countries. Nearly all of the studies had been conducted since 1999. Their analysis of the data involved 2 primary steps: First they conducted a systematic review of all available global prevalence data from studies that were representative at national or subnational levels, and then they employed classical meta-regression methods to estimate women's lifetime prevalence of IPV. They modeled their estimates for 21 global regions, adjusting for variations in the quality and characteristics of studies.

"The results show that globally, in 2010, 30.0% [95% confidence interval (CI) 27.8 to 32.2%] of women aged 15 and over have experienced, during their lifetime, physical and/or sexual intimate partner violence," the authors write.

They note that there was considerable variation from region to region, with East Asia having the lowest incidence, at 16.30% (range, 8.9% - 23.7%), and Central Sub-Saharan Africa having the highest incidence, at 65.64% (range, 53.6% - 77.71), according to the World Health Organization report.

Incidence in North America was reportedly 21.32% (range, 16.2% - 26.4%).

"Given the high prevalence of IPV in all regions of the world, a greater focus on primary prevention is urgently needed alongside the provision of health, social, legal, and other support services," the authors of the Policy Forum write.

The World Health Organization says it will begin immediately to partner with ministers of health, nongovernmental organizations, and sister United Nations organizations to circulate the guidelines and ensure they are properly adapted and used.

The authors have disclosed no relevant financial relationships.

Science. Published online June 20, 2013. Abstract

"WHO Multi-country Study on Women's Health and Domestic Violence against Women." World Health Organization. Full text