Homelessness is an increasing problem in the UK, with rates of homelessness doubling over 2011-2021. Homelessness overlaps with other forms of social exclusion, with homeless people in England having high levels of drug use (20-40% used heroin or crack in last year) and incarceration (25-50% ever incarcerated). These forms of social exclusion are inextricably linked, with people who use drugs having high levels of homelessness (50% currently) and incarceration (69% ever) and incarcerated people having high levels of homelessness upon release (55%).

Homelessness is associated with considerable health harms, including mental and physical illness and heightened infectious disease risk, resulting in their life expectancy being 30 years lower than the general population. The link between homelessness and other social exclusions further increases health harms, with data suggesting that just being homeless doubles mortality risk, while also having experience of incarceration and/or opioid drug use increases mortality risk 8-times. These elevated mortality rates are partly due to homeless people accessing health services late, with homeless people having high rates of emergency department use (48% last year).

Interventions exist to reduce homelessness and its associated health harms, and similarly for people who use drugs and incarcerated people. For homeless people, this includes supported housing interventions, which increase housing stability, improve physical and mental health, and reduce use of emergency departments, drug use and criminal justice involvement.

Although homelessness and other social exclusions (e.g., incarceration) are interlinked, it is unclear the degree to which exposure to one social exclusion increases the likelihood of experiencing another or the degree to which each social exclusion contributes to health harms. Modelling can help get insights to this, but unfortunately no existing studies have modelled the syndemic of homelessness and other social exclusions, and their resulting harms to health—beyond increasing mortality. This will be the focus of this PhD. This PhD project sits at the interface of population health and social sciences and will advance a novel and topical area of research focused on addressing the social determinants of health to reduce health harms in marginalised groups. The student will receive training and develop skills in epidemiological methods and mathematical modelling.

Overall objective: To use modelling to quantify the health harms associated with homelessness and related social exclusions, and assess the possible impact of interventions that act on these social exclusions.

Aims:

1. Use available datasets of homeless people and related groups in the UK to better understand:

The degree to which homelessness overlaps with exposure to other social exclusions and vice versa, and
How exposure to other social exclusions worsens health and intervention/social outcomes among homeless people;
2. Use findings from aim 1 to develop a model of the dynamics of homelessness and related social exclusions for the UK to:

Evaluate the degree to which the risk of being homeless is affected by other social exclusions, and vice versa;
Estimate the health harms resulting from homelessness, and the contribution of other social exclusions to these health harms.
3. Use data from existing interventions (that reduce relevant social exclusions or their health harms) to project their impact on reducing homelessness and their health harms.

The student will join a vibrant and diverse multi-disciplinary research team. The groups at Bristol and Cardiff hold several collaborations nationally, which provide an opportunity for the student to work on various datasets. This project has implications at the national level, with it having the potential to strengthen the public health response for homeless individuals. There is flexibility in refining the project, including in the social exclusions to include, health harms to consider (mental/physical health and/or infectious disease outcomes) and datasets that are analysed. We plan the PhD to focus on the UK, but there are opportunities to focus on other global settings.

Supervisors: Professor Peter Vickerman (Bristol), Dr Jack Stone (Bristol), Dr Ian Thomas (Cardiff) & Professor Peter Mackie (Cardiff)

Funding

These studentships are funded for four years full time through GW4BioMed2 MRC Doctoral Training Partnership. Part time study may also be available. The studentships consist of tuition fees and a stipend matching UK Research Council National Minimum (£20,780 p.a. for 2025/26, updated each year). Additional research training and support funding of up to £5,000 per annum is also available.

Eligibility

Please see the GW4 website for information about eligibility and entry requirements, including specific information for international applicants: GW4 BioMed2 Student FAQs.

How to Apply

A list of all the projects and how to apply is available on the DTP’s website: gw4biomed.ac.uk. You may apply for up to 2 projects and submit one application per candidate only.

Please complete an application to the GW4 BioMed2 MRC DTP for an ‘offer of funding’. If successful, you will also need to make an application for an 'offer to study' to your chosen institution.

Please complete the online application form linked from the DTP’s website by 5.00pm on 20th October 2025. Please note that we may close the application process before the stated deadline if an unprecedented number of applications are received– check the DTP’s website for details and updates. If you are shortlisted for interview, you will be notified from 23rd December 2025. Interviews will be held virtually on 27th and 28th January 2026. Studentships will start on 1st October 2026.

Further Information

For informal enquiries: GW4BioMed@cardiff.ac.uk
For project related queries: Professor Peter Vickerman (peter.vickerman@bristol.ac.uk).