We searched PubMed from Jan 1, 2003, to Dec 31, 2013 to identify papers published in all languages that addressed the epidemiology, risk factors for, and outcomes of chronic non-communicable diseases, infectious diseases, mental disorders, substance misuse, unintentional injuries, geriatric conditions, end-of-life care, and health service use in homeless individuals. We focused our search for articles that discussed high-income countries, including Europe, Oceania, and North America. We
SeriesThe health of homeless people in high-income countries: descriptive epidemiology, health consequences, and clinical and policy recommendations
Introduction
Rates of morbidity and mortality in homeless people are high compared with the general population, in both relative and absolute terms. In some countries, clinical guidelines have identified homeless people as a high-risk group who need targeted interventions. We review the epidemiology and risk factors for morbidity and mortality to guide clinical and policy initiatives regarding homelessness. We first present an overview of definitions and rates of homelessness in high-income countries and then survey the scientific literature about the health of homeless people, before making policy and clinical recommendations.
Section snippets
Definitions of homelessness
Definitions of homelessness vary across countries. Uniform definitions of homelessness have been adopted by many high-income countries in an effort to determine eligibility for services and to track progress in reduction of homelessness, although controversies remain. For example, the Homeless Emergency Assistance and Rapid Transition to Housing (HEARTH) Act of 2012 in the USA builds on previous definitions1 (panel 1), mainly the McKinney-Vento Act.2 The HEARTH Act updates the McKinney-Vento
Causes of homelessness
The causes of homelessness are complex. Current thinking is that homelessness is an interaction between individual and structural factors, including the presence or absence of a safety net.3, 7, 8 Individual factors include poverty,9 early childhood adverse experiences,10 mental health and substance misuse problems,9, 11 personal history of violence,11 and criminal justice system association.12 Evidence suggests that drug and alcohol misuse have strong associations with both the initiation and
Rates of homelessness
Methodological and definition differences create challenges when tracking the number of people who are homeless and comparing rates between countries. The USA conducts an annual point-in-time count, whereby communities across the country must report the number of individuals sheltered nightly in a 10-day period in January; every other year, each community must also count all unsheltered individuals by counting the number of homeless individuals without shelter at night. Canada collects data
Patterns of homelessness
Researchers have defined three categories of homelessness: chronic homelessness, intermittent homelessness, and crisis or transitional homelessness.7, 28 Chronic homelessness is defined as an episode of homelessness lasting more than a year, or four episodes of homelessness in the previous 2 years in an individual who has a disabling condition. Individuals who cycle in and out of homelessness repeatedly, with episodes of homelessness alternating with housing and institutional care (jails,
Ageing of the homeless population
The homeless population is ageing. In the USA, the median age of the homeless population now approaches 50 years. This suggests a cohort effect: individuals born between 1954 and 1965 have experienced homelessness at a higher rate throughout their lives.31 The changing age structure has implications for the health and health-care needs of the homeless population. With younger populations, the focus for health-care providers is to manage and reduce the risk of communicable diseases,
Mortality
Findings from several studies have shown that mortality is substantially increased in homeless people,35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45 with the excess risk most evident in younger people39, 46 and, in some studies, women.35, 41, 42 Causes of excessive mortality include infections (HIV, tuberculosis), ischaemic heart disease, substance misuse, and external factors including unintentional injuries,40 suicides, homicides,46 and poisoning (from medication and illicit substances). Much of
Physical and psychiatric health conditions
Homeless individuals have worse physical and emotional health status than the general population, including those from deprived neighbourhoods.32, 49, 50, 51 The reasons for this are multifactorial and include risk factors that increase individuals' risk for homelessness and are associated with poor health outcomes, such as early life poverty52 and mental health and substance misuse disorders.49, 53 Mental health and substance misuse disorders both increase the risk of and are exacerbated by
Infectious diseases
Most of the studies of infectious diseases in homeless people have focused on tuberculosis, hepatitis C, and HIV.56 Of these three, the highest absolute rate is for hepatitis C (table 2). Despite the wide variations in individual study estimates, one review identified that none of the reported characteristics in the individual studies, such as age, sample size, or underlying population prevalence, could explain the noted high heterogeneity between studies. HIV rates also varied widely with no
Age-related conditions in homeless people
With the ageing of the homeless population, the incidence of chronic diseases and age-related conditions, such as cognitive impairment and functional decline, has increased.32, 74 Researchers have argued that homeless people should be considered eligible for services directed at older adults at age 50, instead of the general populaion cut off of 65.32, 75 This definition is consistent with research in the USA that has identified that homeless veterans are admitted to hospital for
Unintentional injuries
Unintentional injuries are a major cause of morbidity and emergency department use in homeless people57 and represent around 9% of all admissions to hospital for this population; rates are higher than the general or housed poor population, although the discrepancy is greatest in elderly people.58 Substance misuse is more frequently a contributor to injury in the homeless population than in the non-homeless population.57, 96 Results from a study in Boston, USA, showed that 53% of older homeless
Tobacco use
Homeless individuals have high rates of smoking-related diseases, including early onset cardiac disease,80 chronic obstructive pulmonary disease,104 and smoking-related cancers.47 Tobacco use is common in homeless populations; in the USA, 68–80% of homeless people are current smokers,61 which is four times the rate of the overall US population and 2·5 times that of the low-income population.105 Smoking rates in homeless populations in Canada, France, and the UK are similarly increased.106, 107,
Health service use
Homeless individuals have high rates of acute health-care use, including emergency department visits and inpatient admissions to hospital; this pattern is seen across many countries and health-care systems, including in countries with and without universal health-care insurance.49, 117, 118, 119, 120, 121, 122 Homelessness is an important predictor of being a high user of the emergency department, defined as those with more than three to five emergency department visits per year.123, 124, 125
Recommendations for health services, research, and policy
Innovations to health services, new research, and public policy initiatives are necessary to improve the health of homeless people. Health services need to focus on the identification and management of infectious diseases, mental illness, and diseases of old age. Health-care providers need to be aware of the environmental conditions of homeless people and adapt chronic disease management accordingly. Such services will need integration across medical specialties, particularly with treatment
Search strategy and selection criteria
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(2009) Homeless emergency assistance and rapid transition to housing act of 2009. Definition of homelessness. 111th Congress. P.L. 111-22, Sec. 1003