Traumatic brain injury and homelessness: from prevalence to prevention
Authors: Jesse T Young, Nathan Hughes
Journal: The Lancet Public Health (2019)

Traumatic brain injury (TBI) is a major public health issue. Each year, 50–60 million people will experience their first TBI and it is estimated that half of the global population will experience at least one TBI during their lifetime.1Maas AIR Menon DK Adelson PD et al.Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research.Lancet Neurol. 2017; 16: 987-1048Summary Full Text Full Text PDF PubMed Scopus (1028) Google Scholar TBI disproportionately affects young people and is a leading cause of death among children and adolescents in high-income countries.1Maas AIR Menon DK Adelson PD et al.Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research.Lancet Neurol. 2017; 16: 987-1048Summary Full Text Full Text PDF PubMed Scopus (1028) Google Scholar Despite increased education and prevention efforts, the global burden of TBI is increasing.2GBD 2016 Neurology CollaboratorsGlobal, regional, and national burden of neurological disorders, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016.Lancet Neurol. 2019; 18: 459-480Summary Full Text Full Text PDF PubMed Scopus (1532) Google Scholar Emerging evidence suggests that the risk factors for TBI closely align with the social determinants of health and causes of social exclusion, including poverty and marginalisation. Although good evidence shows that socially excluded groups, including people who are homeless, are more likely to die from injury than the general population,3Aldridge RW Story A Hwang SW et al.Morbidity and mortality in homeless individuals, prisoners, sex workers, and individuals with substance use disorders in high-income countries: a systematic review and meta-analysis.Lancet. 2018; 391: 241-250Summary Full Text Full Text PDF PubMed Scopus (347) Google Scholar our understanding of TBI in these groups is poor. In The Lancet Public Health, Jacob Stubbs and colleagues4Stubbs JL Thornton AE Sevick JM et al.Traumatic brain injury in homeless and marginally housed individuals: a systematic review and meta-analysis.Lancet Public Health. 2019; (published online Dec 2)https://doi.org/10.1016/S2468-2667(19)30188-4Summary Full Text Full Text PDF PubMed Scopus (53) Google Scholar evaluate the lifetime prevalence of TBI among people who are homeless or marginally housed. By doing a meta-analysis of 22 studies identified through a systematic review, they generated a pooled estimate of lifetime TBI prevalence in this population of 53·1% (95% CI 46·4–59·7) for any TBI severity and 22·5% (95% CI 13·5–35·0) for moderate to severe TBI. This lifetime prevalence of TBI of any severity is between 2·5-times and 4·0-times higher than estimates for the general population. Of note, the estimated lifetime prevalence of moderate to severe TBI is almost ten-times higher than in the general population. These findings are strong evidence that homeless and marginally housed individuals experience a disproportionate burden of TBI and are a key group for efforts aimed at better identification and treatment. The identification of TBI among homeless or marginally housed people is likely to be particularly challenging because of a high prevalence of severe mental illness, harmful substance use, and profound multimorbidity among this group, and probable diagnostic overshadowing. Accordingly, Stubbs and colleagues recommend increased screening for TBI among homeless or marginally housed individuals in clinical settings and a lower threshold for referral for more accurate, yet costly, neuroimaging diagnostic methods. In a meta-regression, the authors found that the method used to identify TBI significantly affected the estimated prevalence, suggesting that structured interviews are needed to identify those who require further diagnostic testing to ensure equitable access to treatment. Advances in the use of biomarkers could improve the efficiency and accuracy of TBI identification, help guide its subsequent management, and decrease the cost of doing so.5Yue JK Yuh EL Korley FK et al.Association between plasma GFAP concentrations and MRI abnormalities in patients with CT-negative traumatic brain injury in the TRACK-TBI cohort: a prospective multicentre study.Lancet Neurol. 2019; 18: 953-961Summary Full Text Full Text PDF PubMed Scopus (94) Google Scholar These improvements could be especially important among children and adolescents who might not be able to communicate their symptoms effectively.6Stukas S Higgins V Frndova H et al.Characterisation of serum total tau following paediatric traumatic brain injury: a case-control study.Lancet Child Adolesc Health. 2019; 3: 558-567Summary Full Text Full Text PDF PubMed Scopus (15) Google Scholar However, identification and referral to specialist services might not be sufficient to achieve equivalent outcomes among such highly marginalised populations with complex health and social needs. The transient nature of homelessness complicates the ability of clinical services to provide long-term follow-up care and rehabilitation. Therefore, contact with the health system for TBI is a critical opportunity to identify and provide social and housing support to people who are at risk of housing instability. We must acknowledge that even for those who receive evidence-based treatment and rehabilitation, TBI can still result in poor health, functional, and socioeconomic outcomes that can endure over their lifespan.7Steyerberg EW Wiegers E Sewalt C et al.Case-mix, care pathways, and outcomes in patients with traumatic brain injury in CENTER-TBI: a European prospective, multicentre, longitudinal, cohort study.Lancet Neurol. 2019; 18: 923-934Summary Full Text Full Text PDF PubMed Scopus (177) Google Scholar Therefore, prevention must be a central component of public health efforts to reduce the incidence and overall burden of TBI. However, we have a poor understanding of effective injury prevention strategies in marginalised groups and further research is warranted in this field. Among the studies that reported age of first TBI, Stubbs and colleagues calculated a weighted mean age of first TBI of 15·8 years (range 15·0–19·9) and younger age at first homelessness was consistently associated with a history of TBI among the included studies. These findings suggest that providing individuals, particularly young people, with stable housing is important for preventing TBI. It is becoming increasingly clear that TBI can be both a cause and consequence of homelessness.8Binder AS Lancaster K Lengenfelder J Chiaravalloti ND Genova HM Community integration in traumatic brain injury: the contributing factor of affect recognition deficits.J Int Neuropsychol Soc. 2019; 25: 890-895Crossref PubMed Scopus (17) Google Scholar The functional and socioeconomic consequences associated with TBI can present challenges to finding and retaining stable housing.8Binder AS Lancaster K Lengenfelder J Chiaravalloti ND Genova HM Community integration in traumatic brain injury: the contributing factor of affect recognition deficits.J Int Neuropsychol Soc. 2019; 25: 890-895Crossref PubMed Scopus (17) Google Scholar Conversely, a dose-dependent relationship exists between the duration of homelessness and the occurrence of TBI (ie, the longer a person is homeless, the higher the risk of TBI).9Mackelprang JL Harpin SB Grubenhoff JA Rivara FP Adverse outcomes among homeless adolescents and young adults who report a history of traumatic brain injury.Am J Public Health. 2014; 104: 1986-1992Crossref PubMed Scopus (44) Google Scholar Given the increasing evidence for a potential causal relationship, a randomised controlled trial investigating the effect of a housing intervention on TBI incidence is both feasible and warranted. The Housing First model, in which homeless people are provided immediate access to permanent, non-contingent housing, has been found to reduce hospital contact for injury.10Mackelprang JL Collins SE Clifasefi SL Housing First is associated with reduced use of emergency medical services.Prehosp Emerg Care. 2014; 18: 476-482Crossref PubMed Scopus (47) Google Scholar Establishing the effectiveness of a Housing First approach in preventing TBI among people at risk of housing instability should be a public health priority for researchers and policy makers. To ameliorate the substantial TBI burden experienced by homeless and marginally housed people, we must combine efforts to identify and treat TBI with integrated case-management and prevention strategies that address both the housing needs and determinants of social exclusion for those at risk of housing instability. This online publication has been corrected. The corrected version first appeared at thelancet.com/public-health on December 18, 2019 This online publication has been corrected. The corrected version first appeared at thelancet.com/public-health on December 18, 2019 We declare no competing interests. Traumatic brain injury in homeless and marginally housed individuals: a systematic review and meta-analysisThe lifetime prevalence of TBI is high among homeless and marginally housed individuals, and a history of TBI is associated with poorer health and general functioning. Health-care providers and public health officials should have an increased awareness of the burden of TBI in this population. Prospective and longitudinal studies are needed to better understand how the health of this population is affected by TBI. Full-Text PDF Open AccessCorrection to Lancet Public Health 2019; published online Dec 18. https://doi.org/10.1016/S2468-2667(19)30225-7Young JT, Hughes N. Traumatic brain injury and homelessness: from prevalence to prevention. Lancet Public Health 2019; published online Dec 2. https://doi.org/10.1016/S2468-2667(19)30225-7—In this Comment, the reported lifetime prevalence of TBI has been changed to 53·1% (46·4–59·7) from 53·4% (47·6–59·1), and the prevalence of moderate of severe TBI has been changed to 22·5% (13·5–35·0) from 24·9% (16·3–35·9), to reflect corrections made to the linked Article. This correction has been made as of Dec 18, 2019. Full-Text PDF Open AccessA public health prescription for the UK GovernmentOn Dec 12, the people of the UK voted and elected a Conservative party government for the next 5 years. The Conservative party's biggest electoral victory since the 1980s, predominantly based on the promise to "get Brexit done", raises a number of questions about the UK's future. Full-Text PDF Open Access