The public health significance of prior homelessness: findings on multimorbidity and mental health from a nationally representative survey.

Aims: The associations of prior homelessness with current health are unknown. Using nationally representative data collected in private households in England, this study aimed to examine Common Mental Disorders (CMDs), physical health, alcohol/substance dependence, and multimorbidities in people who formerly experienced homelessness compared to people who never experienced homelessness.

Methods: This cross-sectional study utilised data from the 2007 and 2014 Adult Psychiatric Morbidity Surveys. Former homelessness and current physical health problems were self-reported. Current CMDs, alcohol dependence and substance dependence were ascertained using structured validated scales. Survey-weighted logistic regression was used to compare multimorbidities (conditions in combination) for participants who formerly experienced homelessness with those who had never experienced homelessness, adjusting for sociodemographic characteristics, smoking status and adverse experiences. Population attributable fractions (PAFs) were calculated.

Results: Of 13,859 people in the sample, 535 formerly experienced homelessness (3.6%, 95% CI 3.2-4.0). 44.8% of people who formerly experienced homelessness had CMDs (95% CI 40.2-49.5), compared to 15.0% (95% CI 14.3-15.7) for those who had never experienced homelessness. There were substantial associations between prior homelessness and physical multimorbidity (adjusted odds ratio [aOR] 1.98, 95% CI 1.53-2.57), CMD-physical multimorbidity (aOR 3.43, 95% CI 2.77-4.25), CMD-alcohol/substance multimorbidity (aOR 3.53, 95% CI 2.49-5.01) and trimorbidity (CMD-alcohol/substance-physical multimorbidity) (aOR 3.26, 95% CI 2.20-4.83), in models adjusting for sociodemographic characteristics and smoking. After further adjustment for adverse experiences, associations attenuated but persisted for physical multimorbidity (aOR 1.40, 95% CI 1.10-1.79) and CMD-physical multimorbidity (aOR 1.55, 95% CI 1.20-2.00). The largest PAFs were observed for CMD-alcohol/substance multimorbidity (17%) and trimorbidity (16%).

Conclusions: Even in people currently rehoused, marked inequities across multimorbidities remained evident, highlighting the need for longer-term integrated support for people who have previously experienced homelessness.