"It's easy to forget how vulnerable homeless people are," said Margot Kushel, MD, UCSF assistant professor of medicine at San Francisco General Hospital Medical Center and lead author of the study. "Without the safety of a door to close behind them, homeless people are easily victimized."
Among homeless and marginally housed people, transgendered people were at the highest risk, with nearly 12 percent having been sexually assaulted in the prior year. Women also had significantly elevated risk, with 9.4 percent reporting being sexually assaulted in the past year. While the rates of sexual assault in men were lower than those for women, 1.4 percent of homeless and marginally housed men experienced sexual assault in the past year, a surprising finding according to Kushel.
"This lets us know that we need to ask all our homeless patients about their history of sexual violence, not just women," she said.
Risk of sexual assault was lower for women living in low-income single room occupancy (SRO) hotels - considered marginally housed -- than for those living on the streets or in homeless shelters. For men, there was no difference in rates of sexual assault between those living on the street and those in SRO hotels. For both men and women, rates of physical assault were elevated, but did not differ between those who were homeless and those living in SRO hotels, said the researchers.
Not surprising, the researchers found a strong association between mental illness and victimization and between sex work and victimization. "Homeless people with mental illness may not be able to assess risks as well as others and thus may be particularly vulnerable to assault," said Kushel. She added that sex work is common among homeless people and is inherently dangerous work.
Kushel also explained that researchers do not fully understand the extent to which victimization plays a role in prolonging homelessness. "It may well be that victimization plays a role in complicating a person's exit from homelessness. This topic merits further study," she said.
Researchers interviewed 2577 people in San Francisco about their history of recent sexual and physical assault, housing history, sexual practices, substance abuse, heath status and criminal justice history. The main outcome measures were self-reported sexual and physical assault in the previous 12 months.
Overall, study results showed 32.3 percent of women, 27.1 percent of men and 38.1 percent of transgender people reported a history of either sexual or physical assault in the previous year; 9.4 percent of women, 1.4 percent of men and 11.9 percent of transgender people reported sexual assault; and 30.6 percent of women, 26.6 percent of men and 33.3 percent of transgendered persons reported physical assault.
This study has several important limitations, according to Kushel. All data were self-reported, and researchers cannot rule out recall bias. Because questions were administered in English, the researchers may have underestimated Latino and Asian homeless and marginally housed people, she said. In addition, comparing rates of sexual and physical assault with the community norms was complicated by the difficulty of establishing accurate rates in the community. Community rates can be unreliable because of low rates of reporting, lack of uniform definitions of assault and use of different time frames, Kushel said, and the cross-sectional design of the study might have led to over-sampling of chronically homeless people who have higher rates of victimization. On the other hand, inclusion of a relatively stably housed people may bias the estimates downward, she added.
Co-authors include Jennifer L. Evans, MS, and Andrew R, Moss, PhD, both with the UCSF Department of Epidemiology and Biostatistics; Sharon Perry, PhD, with the Division of Geographic Medicine and Infectious Diseases at Stanford University; and Marjorie J. Robertson, PhD, with the Alcohol Research Group at the Public Health Institute in Berkeley, California. The study was supported by a grant from the National Heart, Lung, and Blood Institute and grant from the National Institute of Mental Health and the Agency for Health Care Research and Quality.