The estimates suggest that the global picture varies widely. Countries with the highest rates of sexual violence are those in central sub-Saharan Africa (21%; Democratic Republic of Congo), southern sub-Saharan Africa (17.4%; Namibia, South Africa, Zimbabwe), and Australasia (16.4%; New Zealand and Australia). Countries in North Africa/ Middle East (4.5%; Turkey) and south Asia (3.3%; India, Bangladesh) reported the lowest rates.
After searching systematically for studies published over 13 years (1998) containing data on the global prevalence of women's reported experiences of sexual violence by anyone except intimate partners, Professor Naeemah Abrahams from the South African Medical Research Council in Cape Town, and colleagues from the London School of Hygiene and Tropical Medicine and the World Health Organization, identified 77 suitable studies, compiling data on 412 estimates of violence from 56 countries.
"We found that sexual violence is a common experience for women worldwide, and in some regions is endemic, reaching more than 15% in four regions. However, regional variations need to be interpreted with caution because of differences in data availability and levels of disclosure", explains Abrahams.
Within Europe, countries in eastern Europe (6.9%; Lithuania, Ukraine, Azerbaijan) had a much lower prevalence of sexual assault than central (10.7%; Czech Republic, Poland, Serbia and Montenegro, Kosovo) and western regions (11.5%; Switzerland, Spain, Isle of Man, Sweden, UK, Denmark, Finland, Germany). For more detailed findings for all regions see Lancet paper table 2 page 4.
The authors point out that these data probably underestimate the true magnitude of the issue because of the stigma and blame attached to sexual violence that leads to under-reporting and a lack of good-quality population-based data. Eight regions had data only from one country and many countries had no data at all.
According to Abrahams, "Our findings highlight the need for countries to have their own population-based data on the levels of sexual violence by different perpetrators to improve understanding of the magnitude of the problem and the main risk factors, and to develop appropriate policies and responses, including primary prevention interventions and comprehensive services to treat victims of sexual assaults."
Writing in a linked Comment, Kathryn Yount from Emory University, Atlanta, USA describes the study as "a landmark in its scale and rigour", saying that, "The major contribution of this study is its comprehensive inclusion of data to derive best estimates for the worldwide prevalence of non-partner sexual violence against women. An estimated prevalence of 5.2 % is unacceptably high on public health and human rights grounds and, hopefully, will spur timely and systematic discussions about the use of standard definitions and improved research tools and data collection methods to improve disclosure of a highly stigmatised violation…The data confirm that non-partner sexual violence is neither rare nor geographically isolated and, thus, that existing laws and systems of accountability remain inadequate. Effective responses will require widespread legal and institutional change."