Note

This material is the result of work supported with resources and the use of facilities of the Houston VA Health Services Research & Development Center of Excellence (HFP90-020) at the Michael E. DeBakey VA Medical Center. The views expressed reflect those of the authors and not necessarily those of the Department of Veterans Affairs, the US government or Baylor College of Medicine.

Introduction

Each year in the United States, more than 3 million people experience homelessness (1). On a single night alone, about 650,000 people are homeless (2). While the US government has made efforts since the 1980s to develop policies and design services to address the problem of homelessness, it remains an intractable public health concern that continues to challenge policymakers and service providers with its magnitude and complexity (3).
Although homelessness affects all sectors of society, older adults are an especially vulnerable subpopulation of the homeless. With aging come a number of additional challenges that differentiate the challenges homeless elders face from those faced by younger populations and families. Because the elderly homeless are often mentally and physically frail, they are more liable to victimization in shelters and on the streets. With homelessness, the unsafe and unsanitary living conditions aggravate elderly people’s acute and chronic health problems, which may also interfere with effective treatment of their diseases. Beyond impairing elderly people’s ability to meet basic needs for food, shelter, and safety, homelessness also deprives them of physical, mental, and spiritual health (4).
Despite the unique challenges that the homeless elderly face, the research on homeless elders remains limited. Much of the data about elderly homeless is hidden within aggregate information about homeless populations in general, but the elderly homeless are likely significantly different from their younger counterparts in terms of factors including – but not limited to – demographics, pathways into homelessness, and unmet medical care needs. Given these differences, effective policies need to address this subpopulation more specifically; and a first step towards that involves gathering information about the prevalence and causes of homelessness among the elderly.
While there have been scattered observations in recent literature about the increasing average age of the homeless population in the United States (5, 6), no systematic review has been done regarding the prevalence of elderly homeless among the general homeless population. Understanding the prevalence of older adults within the homeless population is a first step towards understanding the magnitude of the problem and should be useful for agencies in charge of planning services. Moreover, understanding the factors that contribute to elderly homelessness is another basic requirement for developing preventive measures and services for the elderly homeless population. This review aims to examine the literature on the prevalence of homeless who are older adults and identify causes of elderly homelessness in an effort to increase awareness about the scope of the problem.

Method

The searches for the prevalence of older homeless persons and causes of elderly homelessness were initially done simultaneously. Electronic databases – including Medline, Cochrane Review, and GoogleScholar – were searched. Manual searches of citation indices, bibliographies of located articles, and Google were also searched for relevant articles. Search strategies included the terms homeless, homelessness, elder, elderly, aged, and in old age in the title.
For prevalence studies of elderly homeless, studies were included if they examined a US population, had data that identified a subpopulation of elderly homeless, and were conducted after 2000. Not all of the studies had definitions of what constituted elderly homelessness. However, the literature seems to be trending towards a lower bound of 50 years of age:  having aged prematurely, homeless individuals over age 50 have chronic health problems and morbidities normally associated with those over 65 years in the general population, and they are unlikely to return to their jobs (6, 7).  In studies that did not have a grouping that included the 50-year-old limit, the next closest demographic group was included in the data (provided that it was ± 5 years of 50). When possible, the upper limit was chosen to have a more conservative estimate. Thus, for example, Meschede’s 2004 study (8) grouped its data from 45-54 years old, and then another group at 55 years and older; so the prevalence numbers in this article include the 55+- year-old group.
Studies carried out before 2000 were excluded because the prevalence of elderly homeless has likely changed significantly since then. Some studies included multiple iterations of prevalence done at different time periods but using the same method and conducted in the same location – in such instances, only the last time period of information was included in this review. Notably, only studies that had quantitative data on the prevalence of the elderly homeless were included – while this decision might seem overly exclusive of studies that have descriptive data, the purpose of this review is to capture the range of prevalence in numbers in the extant literature. 
For factors leading to elderly homelessness, studies were limited to those with a US population and those specifically focused on predisposing factors or triggering events in an elderly homeless population. No date constraint was put on the viability of elderly homelessness (unlike the prevalence of elderly homeless) for two reasons: (1) the literature about causes of elderly homelessness was much smaller, and (2) reasons for elderly homelessness are unlikely to be as time-sensitive as prevalence.

Results

From Medline, 511 results came back using the search “((homeless[Title]) OR (homelessness[Title])) AND (elderly OR in old age OR elder OR aged) AND (english[language]) AND "epidemiology"[meSH subheading].” Studies that were excluded included studies not conducted in the United States, and studies that focused on too-specific populations (e.g., homeless mothers, veterans, the HIV positive). For the prevalence search, studies that did not have a breakdown of their population subjects by age were excluded, as were studies conducted before 2000. Through Medline, two studies (9, 10) were identified for the prevalence search; and one study (11) was identified for the search of factors contributing to homelessness. Additional searches of Medline were done using MeSH headings of “Homeless Persons/statistics & numerical data,” which identified two more sources about prevalence: Swigart and Kolb (12) and Brown, Kimes, Guzman and Kushel (13). A search for contributing factors to homelessness on Medline produced the Keigher & Greenblatt article (14). The search of the Cochrane Review returned 0 results. A search on GoogleScholar returned 5,920 searches, although only the first 400 returns based on “relevancy” were examined; using the same exclusionary criteria detailed above for the Medline search, this search retrieved two sources, the Annual Report to Congress (2) and an article by Hecht & Coyle (15). Two articles about prevalence, Meschede, Sokol and Raymond (16) and Hahn et al. (17) and one report from the Shelter Partnership (18) about contributing factors to homelessness were found by manually searching the bibliography of a GoogleScholar search article by Sermons and Henry (19).  A search on Google produced the report by George et al. (20), which analyzed both prevalence and contributing factors to homelessness, and the Hearth report (21), which looks at contributing factors. Overall, nine articles for the prevalence search (see Tables 1A-C) and six articles for the contributing factors (see Table 2) were found that matched the criteria set forth above.

Table 1A

Prevalence Studies That Focused on Homeless

Table 1B

Prevalence Studies Based on Outreach Events to the Homeless

Table 1C

Prevalence Studies Based on Homeless

Table 2

Contributing Factors of Homelessness //bold = one of the top three reasons

Prevalence
The prevalence studies were divided into three groups on the basis of whether they (1)   comprehensively focus on homeless populations; (2) present data based on information gathered at outreach events for the homeless, or (3)  sample shelters.  They are described in Tables 1A, 1B, and 1C, respectively.
The four prevalence studies that focus on homeless populations more comprehensively than the other studies were those that included, but were not limited to, shelter populations and clients of other homeless-oriented services (9, 10, 17,20). The range of prevalences of the elderly in the homeless population was from 20% (10) to 38% (9).
The two prevalence studies based on outreach events to the homeless reported the two highest prevalences of elderly homeless, at 55% (12) and 39% (13).This might reflect a tendency for elderly homeless to seek out services that the younger homeless do not. While this requires more systematic research, it also represents an important implication for public policy and a potential opportunity for reaching the elderly homeless.
Three prevalence studies looked solely at the clients of shelters and housing services for the homeless (2,15,16). These tended to be on the lower side of the prevalence studies, ranging from 8% (15) to 24% (2). Again, this may reflect something of a pattern of the elderly homeless – are they less likely than their younger counterparts to seek housing services? – but it is also an area that requires more research.
Overall, the median prevalence of elderly homelessness was 24%, reflecting a definite rise from the 1990s, when the prevalence was estimated to be around 11% (17).   Furthermore, the current prevalence of the US general population that is older than 50 is 32%, compared with the 1990s, when the prevalence was 25% (22).
Factors Leading to Homelessness
We identified seven studies in the search for causes of homelessness, which come from six sources (11, 14, 15, 18, 20, 21). The Shelter Partnership (18) has two entries in Table 2 because it focused on two different subpopulations (New Image Shelter, Rainbow Apartments). To be able to identify trends from the different studies, seven categories of risk factors for homelessness were created for this review, adapted from how the studies themselves categorized the risk factors. These categories are financial/employment problems, housing problems, lack of social support, physical health problems, mental illness, substance use and gambling disorders), and criminal history. While the tables provide the exact percentages for each category when possible, the discussion that follows focuses only on the top three reasons for homelessness within each study so as to better draw comparisons among the studies. For studies that did not permit calculations of exact percentages by category (14, 20), the important factors mentioned in the studies were isolated and marked with Xs in Table 2.
Financial and employment problems and lack of social support were the most commonly cited factors leading to homelessness. Six of the seven surveys (11, 14, 15, 18, 20) listed financial and employment problems among the top causes of homelessness, with most of the studies showing that this was the most common reason for homelessness. Lack of social support is a broad category that included domestic violence and conflict with or death of a loved one, as well as interpersonal conflict with landowners, co-tenants, and neighbors. It was among the main causes of homelessness in six studies (including both samples of the Shelter Partnership study (11, 14, 18, 20, 21).
Health issues were separated into two categories, physical and mental health problems, because most studies noted them separately and because the policy implications are different for both. Nonetheless, comparison across all seven studies is difficult because one study did not distinguish between physical and mental health problems (12). Still, health problems of any sort were noted as a main cause of homelessness in four studies (11,14,20,21). Interestingly, mental health alone seems to be more prominent an issue than physical health, as mental health alone was cited as a main factor for homelessness in two of three studies that distinguished mental from physical health problems (11,14, 21).
Addictions (including drugs, alcohol, and gambling) were listed as main factors of homelessness in three studies (15, 18, 20) (in the Rainbow Apartments population of the Shelter Partnershp study). While addictions are arguably a form of mental illness, they make up a separate category because most studies listed them out separately. One can surmise that they separated out addictions as another category because the mental health services that address addictions are distinct from other mental health illnesses.
Criminal behavior and consequential jail time were noted as reasons for homelessness in four studies (11, 15, 18) (in both samples of the Shelter Partnership study). It ranked among the top three causes of homelessnesss in only one of them, the Shelter Partnership New Image Shelter study (18).
Housing problems is a category that includes the housing that individuals were formerly living in being sold, converted, or rehabilitated; as well as eviction. Two surveys cited housing problems as among the main causes of homelessness (14,15).
Overall, the most consistent pattern among the surveys is that financial and unemployment problems, as well as interpersonal conflict, are some of the main factors leading to elderly homelessness. Next in frequency are mental health problems, followed by physical health problems and addictions, then housing problems and criminal activity as the least frequently cited problems.

Discussion

This review found that the prevalence of the elderly homeless ranges from 8% (15) to 55% (12) of the homeless population, with a mean prevalence of 27% and a median prevalence of 24%. It also found that contributing factors to homelessness include financial/employment problems, interpersonal conflict, and mental health problems as the top reasons leading to homelessness. Overall, this highlights the need for increased attention to the elderly homeless as a significant part of the homeless population and sheds light on specific services that might benefit the elderly homeless.
The finding that the elderly homeless make up about one fourth of the homeless population is in stark contrast to the last definitive review of elderly homelessness by the Institute of Medicine, in which all but one study reported a prevalence of elderly homeless of less than 10%  (23). The landscape of the homeless population has shifted and will likely continue to trend towards an increasing elderly homeless population as people live longer. Elderly homelessness deserves a special focus, both in terms of research and resources allocated to this subpopulation.
Among the ways in which the needs of the elderly homeless differ from their younger counterparts is the increased physical and mental frailty of elderly homeless. The elderly homeless are more much more likely than their younger counterparts to have chronic medical conditions, to have two or more medical conditions (including hypertension and arthritis), and to suffer from mental health disorders (24). This is not only a reflection of the inherent and gradual aging process, as well as the accumulation of physical and mental insults that the elderly homeless have weathered, but also a reflection of how homelessness itself may have precipitated latent disorders. One study (25), an extension of the Chicago prevalence study mentioned above (20), further explored providers’ perspectives of the unique mental health needs of the elderly homeless and their implications for service provision. He found that many ex-criminals and veterans, subpopulations that are disproportionately high in the older homeless population (corroborated by studies such as that of Hecht & Coyle [15]), would benefit from specific programming targeting their anxiety, adjustment, and PTSD issues. Other unique aspects about the situation of the elderly homeless that providers should be cognizant of include that dementia complicates the medication management of this group; that grief is more disabling, as losing loved ones depletes an already shrinking social network; and that intensified suspicion and isolation prevent many elderly homeless from seeking mental health help (25).  Unfortunately, the obvious need for more health care in elderly homeless is not reflected in health utilization patterns: multiple studies have documented that the elderly homeless seek medical care at about the same rates – if not less – than their younger counterparts (7, 26-28).  
This review found that financial and employment difficulties are among the top contributing factors to elderly homelessness. Vocational rehabilitation – while likely a need in the general homeless population – is even more necessary in the elderly homeless population for a number of reasons. Factors such as ageism from employers, lacking requisite job skills, an erratic work history, and a questionable longevity that renders investing in an older employee a higher risk are all particularly discouraging for the elderly homeless (29). Moreover, while the elderly homeless are now often defined as 50 years of age, many welfare services are available only to those who have recognized the more “official” thresholds of old age (11). This, in turn, means that there is a significant gap for the “younger” elderly homeless who have the physiologic needs of a much older person but do not qualify for institutional support.
Understandably, lack of social support also ranked among the top reasons contributing to elderly homelessness. With age comes a deterioration of social ties as one’s peers pass away and one becomes less autonomous. Interestingly, housing problems was lower on the list of factors involved in elderly people’s becoming homeless. This might reflect a trend for elderly people, i.e., that many elderly people live with friends or family members, rather than by themselves, so interpersonal conflict is more likely to have more serious ramifications (i.e., could result in an older person’s becoming homeless.
Our findings in this study suggest several aspects of this topic that require further research. First, in examining the literature on elderly homelessness, the lack of consistency in even the most basic definitions was glaringly clear. The lack of a consensus definition about what constitutes “elderliness” in the homeless population hinders research about this vulnerable subpopulation because it is difficult to identify subjects in a consistent manner. As a result, studies have adopted different age limits to suit their varying needs, which makes studies harder to compare and use as a basis for drawing conclusions.
Second, more research is needed to elucidate the specific patterns and behaviors of the elderly homeless to identify service barriers and discern how services can be optimally delivered to the elderly. For example, the studies that were based on outreach to homeless people had much higher prevalence estimates of the elderly homeless than prevalence studies based on shelter counts. Does this discrepancy reflect a tendency for elderly homeless to avoid shelters – perhaps out of fear of being victimized by other younger homeless people overnight – and instead view outreach events as more transient forms of help that are, thus, safer? Evidence suggests that elderly homeless often feel uneasy about staying in sheltering facilities because of perceived danger, and that younger homeless people are often viewed as a source of this danger (29-31). One model to address this was to separate homeless services for the elderly from those for the other homeless (30), but more research needs to be done to see whether this anecdotal experiment can be translated more systematically.
Third, given that the elderly homeless and rural homeless are individually both often overlooked subpopulations, it follows that there is little literature about the intersection of the two. Most studies used in this review come from areas dominated by urban cities, which may hide the prevalence and needs of the elderly homeless in rural areas (23). If rural homelessness is more “hidden” than urban homelessness, the elderly homeless in rural areas are even more hidden than their urban counterparts.
Fourth, although this review did not find that addictions ranked among the top issues that contribute to homelessness among the elderly, the studies were based on self-assessment and self-report. Given that the nature of addiction blinds the person struggling with it to the devastating toll it incurs on him/herself, it may behoove planning committees for the elderly homeless to more systematically screen for alcohol and drug addictions among this population. This would more accurately identify the needs for counseling and group therapy in the elderly homeless, who may have long ago despaired of ever being able to conquer their addictions.