Homelessness as a predictor of mortality: an 11-year register-based cohort study
The purpose of this study was to examine the association between homelessness and psychiatric disorders, including substance use disorders, on one hand, and cause-specific and all-cause mortality on the other in a high-income country.
A historical nationwide register-based cohort study of the Danish population from 15 years of age between 2000 and 2011 was conducted. The association between homelessness, psychiatric disorders, and mortality was analysed by Poisson Regression adjusting for important confounders. Standardised mortality ratios (SMRs) were calculated for people with a history of homelessness compared with the general population using direct age-standardisation.
During 51,892,324 person-years of observation, 656,448 died. People with at least one homeless shelter contact accounted for 173,592 person-years with 4345 deaths. The excess mortality in the population experiencing homelessness compared with the general population was reduced by 50% after adjusting for psychiatric diagnoses, including substance use disorders (mortality rate ratio (MRR) for men 3.30, 95% CI 3.18–3.41; women 4.41, 95% CI 4.14–4.71). Full adjustment including physical comorbidity and socioeconomic factors in a sub-cohort aged 15–29 years resulted in an MRR of 3.94 (95% CI 3.10–5.02) compared with the general population. The excess mortality associated with homelessness differed according to psychiatric diagnosis, sex, and cause of death.
A mental health or a substance use disorder combined with homelessness considerably increases the risk of death. However, homelessness is also independently associated with high mortality. Differences in the association between homelessness and mortality in men and women suggest the need for sex-tailored interventions.
KeywordsHomeless persons Mortality Mental disorders Substance abuse Epidemiology
Supported by the University of Copenhagen, Department of Clinical Medicine.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 10.Baggett TP, Chang Y, Singer DE, Porneala BC, Gaeta JM, O’Connell JJ, Rigotti NA (2015) Tobacco-, alcohol-, and drug-attributable deaths and their contribution to mortality disparities in a cohort of homeless adults in Boston. Am J Public Health 105(6):1189–1197CrossRefPubMedPubMedCentralGoogle Scholar
- 19.Pedersen CB, Gotzsche H, Moller JO, Mortensen PB (2006) The Danish Civil Registration System. A cohort of eight million persons. Dan Med Bull 53(4):441–449Google Scholar
- 20.The National Social Appeals Board (2015) The Danish homeless register 1999–2011 http://www.ast.dk/. Accessed 1 July 2017
- 22.World Health Organization (1967) Manual of the International Classification of Diseases (ICD-8). World Health Organization, GenevaGoogle Scholar
- 23.World Health Organization (1992) The ICD-10 Classification of mental and behavioural disorders. Clinical descriptions and diagnostic guidelines. World Health Organization, GenevaGoogle Scholar
- 25.Lynge E, Sandegaard JL, Rebolj M (2011) The Danish National Patient Register. Scand J Public Health 39(7 Suppl):30–33Google Scholar
- 27.Thygesen SK, Christiansen CF, Christensen S, Lash TL, Sørensen HT (2011) The predictive value of ICD-10 diagnostic coding used to assess Charlson comorbidity index conditions in the population-based Danish National Registry of Patients. BMC Med Res Methodol 11:83Google Scholar
- 28.Petersson F, Baadsgaard M, Thygesen LC (2011) Danish registers on personal labour market affiliation. Scand J Public Health 39(7 Suppl):95–98Google Scholar
- 30.SAS CUSTOMER SUPPORT (2012) Analyzing survival data with competing risks using SAS® Software http://support.sas.com/resources/papers/proceedings12/344-2012.pdf. Accessed 1 July 2017
- 42.Benjaminsen L, Andrade SB (2015) Testing a typology of homelessness across welfare regimes: shelter use in Denmark and the USA. Housing Studies:1–19Google Scholar
- 43.Dan Church Social (2015) KOMPASSET. http://kompasset.kirkenskorshaer.dk/. Accessed 2 Feb 2015