A Systematic Review of the Epidemiology of Nonfatal Strangulation,a Human Rights and Health Concern

We reviewed the literature on the epidemiology of nonfatal strangulation (also, albeit incorrectly, called choking) by an intimate partner.We searched 6 electronic databases to identify cross-sectional, primary research studies from 1960 to 2014 that reported national prevalence estimates of nonfatal strangulation by an intimate partner among community-residing adults. Of 7260 identified references, 23 articles based on 11 self-reported surveys in 9 countries met the inclusion criteria. The percentage of women who reported ever having been strangled by an intimate partner ranged from 3.0% to 9.7%; past-year prevalence ranged from 0.4% to 2.4%, with 1.0% being typical.Although many epidemiological surveys inquire about strangulation, evidence regarding its prevalence is scarce. Modifying or adding a question to ongoing national surveys, particularly the Demographic and Health Surveys, would remedy the lack of data for low- and middle-income countries. In addition, when questions about strangulation are asked, findings should be reported rather than only combined with other questions to form broader categories (e.g., severe violence). Such action is merited because of the multiple negative short- and long-term sequelae of strangulation.Intimate partners hurt one another in many ways. Few specific acts of nonfatal abuse, however, are associated with as wide of a range of health problems or are as difficult to detect as strangulation.Strangulation is defined by reduced blood flow to or from the brain via the external compression of blood vessels in the neck. Manual strangulation (i.e., gripping the throat with one’s hands) appears to be the most common method of strangulation in intimate partner violence (IPV), although ligatures (e.g., belts, scarves) are sometimes used. The application of 4 pounds of pressure is required to occlude jugular veins, and 5 to 11 pounds (roughly the pressure required to can vegetables or the recommended pressure for very light polishing of a motor vehicle) are required to occlude carotid arteries.1 Consciousness is lost in 10 to 15 seconds, and death can occur within 3 to 5 minutes.1Being strangled is extremely painful,2 and not being able to breathe is frightening even in controlled laboratory experiments.3 In addition to the psychological implications of such intimidation, a uniquely wide range of neurological and physical outcomes are associated with strangulation. Nonfatal intentional strangulation causes immediate symptoms (e.g., loss of consciousness, which recedes quickly; loss of sphincter control; a raspy voice, which sometimes becomes chronic), symptoms that appear a few hours later (e.g., petechiae on the face and eyes), symptoms that appear a few days afterward (e.g., ear bleeding; bruises, the immediate lack of which decreases acknowledgment of the injury event by police and others), and sometimes mental and physical health problems (e.g., stroke) that are manifested months later. In addition, strangulation with a loss of consciousness can result in mild brain injury. Multiple strangulations are reported among one third to as many as three fourths of women in domestic violence emergency shelters.4,5Strangulation is a relatively common cause of homicide death, particularly for women. We compiled data available through the World Health Organization6 to document the risk of homicide by asphyxiation among women around the globe and to illustrate gender differences in the risk of homicide by asphyxiation. As shown in Figure 1, rates vary widely, and many countries, particularly low-income countries, report no cases or have no data. Figure 2 documents that asphyxiation accounts for a higher percentage of homicides of women than of men. These mortality data are, as will be seen, paralleled by self-reported data. Moreover, as was found in a recent systematic review of intimate partner homicide in 66 countries, 6 times as many homicides of women (vs men) are by an intimate partner.7 Unfortunately, most mortality data, regardless of country, do not routinely include both means of death and the victim–suspect relationship.Open in a separate windowFIGURE 1—Homicide by asphyxiation, per 100 000 women aged ≥15 years old.Note. Rates shown are the average of up to five of the most recent years of data available for each country. Data were obtained from the World Health Organization’s Detailed Mortality Database. Mortality, ICD 10. Available at: http://www.who.int/healthinfo/statistics/mortality_rawdata/en/index.html. Accessed February 14, 2013.Open in a separate windowFIGURE 2—Percentage of homicides by asphyxiation among those aged ≥15 years old by (a) women and (b) men: Systematic Review of the Epidemiology of Nonfatal Strangulation, 1960–2014.Note. Rates shown are the average of up to five of the most recent years of data available for each country. Data were obtained from the World Health Organization’s Detailed Mortality Database. Mortality, ICD 10. Available at: http://www.who.int/healthinfo/statistics/mortality_rawdata/en/index.html. Accessed February 14, 2013.The unique nature of and the wide-ranging health outcomes following strangulation are broadly acknowledged. Such acknowledgment has extended to policy in some locales. For example, as of May 2012, approximately 30 US states had enacted separate statutes regarding strangulation.8 The federal government’s funding of the recently established National Strangulation Training Institute9 is further evidence of the growing acknowledgment of the importance of strangulation in IPV.We conducted the present systematic review to estimate the scope of nonfatal strangulation in intimate relationships, to describe key findings, and to offer suggestions for future research.