Full length articleFactors associated with cognitive impairment in a cohort of older homeless adults: Results from the HOPE HOME study
Introduction
The median age of single homeless adults in the United States is rising, and now approaches 50 (Culhane et al., 2013; Hahn et al., 2006). Those born in the latter half of the baby boom (1954–1963) have had an elevated risk of homelessness throughout their lives (Culhane et al., 2013). For older homeless adults, chronic medical conditions, including geriatric syndromes, are causally linked to healthcare utilization and mortality (Brown et al., 2016b, Brown et al., 2012, Garibaldi et al., 2005, Gelberg et al., 1990).
Prior studies have found a high prevalence of cognitive impairment among homeless adults (point estimates range from 4 to 40%) and impairment occurring at an earlier age than in the general population (Brown et al., 2012, Buhrich et al., 2000, Burra et al., 2009, Depp et al., 2015, Gonzalez et al., 2001, Nishio et al., 2015, Pluck et al., 2011, Spence et al., 2004). However, the majority of these studies relied on samples either recruited from shelter environments, which may not be representative of the homeless population overall, (Burra et al., 2009, Spence et al., 2004) or from specific populations (e.g., persons with mental health conditions) (Bousman et al., 2010, Seidman et al., 1997, Stergiopoulos et al., 2015). Most studies of cognitive function in homeless adults have used global tests of cognition (e.g., Modified Mini Mental Status Exam [MMSE]) (Burra et al., 2009, Depp et al., 2015). Few studies have examined specific domains, such as memory and executive function (Bousman et al., 2010, Brown et al., 2012, Ennis et al., 2014). Executive function is defined as high-level cognitive processing involved in the control and regulation of goal-directed behaviors (Alvarez and Emory, 2006). Studies of homeless adults recruited from shelters identified a high prevalence of executive dysfunction (Brown et al., 2012, Gonzalez et al., 2001, Seidman et al., 1997, Seidman et al., 2003). Preserved executive function is essential to making plans, prioritizing, and completing tasks and thus may be of particular importance to homeless adults attempting to navigate complex social services to address their basic needs (Burra et al., 2009).
There is a poor understanding of the risk factors associated with cognitive impairment in homeless adults. Potential explanations include comorbid conditions such as vascular disease, substance use, traumatic brain injury (TBI), neurodevelopmental disorders, and psychiatric disease (Backer and Howard, 2007). Alcohol misuse and TBI are known causes of cognitive impairment in the general population (Brandt et al., 1983, Gardner et al., 2017), but few studies have explored these risk factors among homeless adults (Seidman et al., 2003, Topolovec-Vranic et al., 2012). We evaluated global cognitive function and executive function in a population-based sample of homeless adults aged ≥50. We chose this age range because of the high prevalence of geriatric conditions occurring in homeless adults 50 and older (Brown et al., 2012, Brown et al., 2013). We examined the relationship between substance use, TBI, and cognitive impairment, hypothesizing that high-risk substance use and a history of traumatic brain injury (TBI) are associated with cognitive impairment.
Section snippets
Participants
During July 2013–June 2014, we enrolled a population-based sample of 350 homeless adults from overnight shelters, homeless encampments, meal programs, and recycling centers in Oakland, California for the Health Outcomes in People Experiencing Homelessness in Older Middle agE (HOPE HOME) study. This outreach approach expanded on prior methods (Burnam and Koegel, 1988) to include homeless encampments and recycling centers to ensure inclusion of unsheltered adults. We recruited individuals from
Sample description
Of 350 participants enrolled in the HOPE HOME study, we included data from 343 participants. We excluded one participant who had visual impairment, three participants who were intoxicated during the assessment, two participants who could not read or write, and one participant with limited English fluency. Six individuals declined to complete the TMTB assessment and we excluded TMTB data for an additional participant due to a stopwatch malfunction (n = 336 for TMTB outcome) (Fig. 1).
Participants
Discussion
In a population-based sample of older homeless adults with a median age of 58, we found a prevalence of impairment in global cognitive function (25.1%) and executive function (32.9%) three to four times higher than the reported prevalence in populations more than 10 years older. In a national sample of adults 70 years and older in 2002, 9% demonstrated cognitive impairment on a telephone interview cognitive scale (Langa et al., 2008). Early age of onset of cognitive impairment, defined as the
Conclusions
We found a high prevalence of global cognitive and executive function impairment in our population-based sample of older homeless adults. Cognitive impairment was associated with high-severity alcohol use. Our results have several implications. First, policy-makers should consider cognitive impairment when designing supportive housing, intensive case management programming, substance use treatment, and healthcare delivery for older homeless adults. Second, clinicians should screen homeless
Role of funding source
This study was funded by grants from the National Institute on Aging (NIA): R01AG041860 [Kushel, Ponath, Guzman], K24AG046372 [Kushel, Guzman and Tieu], P30AG15272 [Johnson], and P30AG044281 [Kushel]. These funding sources had no role in the preparation, review, or approval of the manuscript and do not necessarily represent the official views of the NIH or AHRQ.
Dr. Hurstak receives fellowship support from National Institute of HealthT32HP19025.
Contributors
Drs. Hurstak and Kushel had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Kushel, Ponath.
Acquisition of data: Kushel, Ponath, Weyer-Jamora.
Statistical analysis: Hurstak, Guzman.
Analysis and interpretation of data: Hurstak, Johnson, Kushel, Lee, Weyer Jamora.
Drafting of the manuscript: Hurstak, Kushel, Johnson, Tieu.
Critical revision of the manuscript for important intellectual
Conflict of interest
Dr. Kushel is a member of the leadership board of Everyone Home, which seeks to end homelessness in Alameda County, CA. No other conflicts of interest were reported.
Acknowledgements
The authors gratefully acknowledge their colleagues Angela Allen, Pamela Olsen, Nina Fiellin, Tauni Marin, and Kenneth Perez for their invaluable contributions to the HOPE HOME study. The authors also thank the staff at St. Mary’s Center and the HOPE HOME Community Advisory Board for their guidance and partnership.
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