This is a plain English summary of an original research article
Socially excluded men have a mortality rate that is nearly eight times higher than the average for other men, and it is almost 12 times higher for excluded women. These health inequities in outcomes exist across a wide range of health conditions, particularly in infectious diseases and mental health. These findings suggest the need for a joined-up approach across sectors to support inclusive services and policies.
Populations who experience social exclusion included in the NIHR-supported study were homeless people, sex workers, people with substance use disorder and those in prison. However, other marginalised groups not included in this study do exist and also need to be considered when implementing services.
This review shows higher rates of excess deaths in these groups than was previously known. The effect was marked, and consistent across the different groups studied.
These researchers recommend that not only should interventions address particular infectious diseases strongly associated with being on the margins of society, such as hepatitis, but also more common non-communicable conditions such as cardiovascular disease where excluded groups are at greater risk.
Why was this study needed?
A large body of research exists on the health outcomes linked to inequities using various measures of deprivation such as socioeconomic status, neighbourhood and occupation. However determining the burden of disease can be difficult in marginalised groups such as sex workers, homeless people, drug users and people in prisons as they are often absent from health information systems. The number of people who may be affected is increasing. As Shelter pointed out last year, there are now over 300,000 homeless people, including those sleeping rough, in the UK.
A wide range of initiatives in public health and social domains are grounded in the association between ill health and social deprivation. Finding ways to address the societal impacts of communicable disease and severe mental illness is a priority across the socioeconomic spectrum as these conditions have consequences for society as a whole.
Although individual studies have observed high death rates from various causes among these groups, the results have not previously been compiled in a review, hence the need for this study.
What did this study do?
This large systematic literature review and meta-analysis pooled data from 337 studies. The research was published between 2005 and 2015 and looked at disease and death outcomes in those with a history of homelessness, substance use disorder (not including alcohol or cannabis use), sex work or those who had been imprisoned.
Studies included were systematic reviews, meta-analyses, observational studies and interventional studies from 38 high-income counties. Most of the data came from the US, Australia, Sweden, Canada or the UK.
There was wide variability between the study types and definitions of marginalisation which reduces confidence in the precision of the pooled results. There are also differences in care and health systems serving these different excluded groups and for different countries. However, the differences were large enough to suggest these are real effects.
What did it find?
- Taking age into account, socially excluded men had a mortality rate almost eight times higher than the average (standardised mortality ratio [SMR] 7.88, 95% confidence interval [CI] 7.03 to 8.74, 30 studies) and socially excluded women almost 12 times higher than the average (SMR 11.86, 95% CI 10.42 to 13.30, 29 studies).
- Death rates from infectious and parasitic diseases were almost three times higher in socially excluded men than the average (SMR 2.83, 95% CI 1.61 to 4.05) and almost six times higher in socially excluded women (SMR 5.58, 95% CI 1.46 to 9.70).
- Deaths due to poisoning, injury and other external causes were nearly eight times higher in socially excluded men (SMR 7.89, 95% CI 6.40 to 9.37) and nearly 19 times higher in socially excluded women (SMR 18.72, 95% CI 13.73 to 23.71).
- Prevalence of death from cardiovascular disease, respiratory disease, cancer and asthma was also significantly increased in socially excluded groups, and relative risks are consistently higher in females than males.
What does current guidance say on this issue?
NICE 2016 guidelines suggest that individuals in contact with the criminal justice system should go through two health assessments to identify immediate and longer-term needs. They should be screened for infectious diseases such as HIV and hepatitis B or C and offered health advice on potential risk factors such as diet, exercise, sexual health, alcohol, smoking and substance use. Staff members should be aware of the possibility of unidentified or emerging mental health issues.
To reduce health inequalities, NICE guidelines in 2016 recommend all key stakeholders including community and voluntary organisations work together to develop initiatives.
There are resources for action to improve health for particular disadvantaged groups, for instance, recent information from Public Health England on improving homeless health
A systematic review by Luchenski published in the Lancet at the same time as this research found that multicomponent interventions are more effective when targeting groups of socially excluded people than interventions directed at individuals.
What are the implications?
The review highlights the substantial burden of disease faced by socially excluded and marginalised societal groups, with the disparity consistently higher in females compared with the average. A cross-sector response to prevent social exclusion and develop services and policies that support inclusion could minimise the number of people facing these inequalities.
The studies were all from high-income countries; many may differ from the UK regarding population and landscape. However, the scale of the gaps identified is large.
Other groups who may experience social exclusion such as ethnic, sexual and gender minorities also need to be considered.
Citation and Funding
Aldridge 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;391:241–50.
This project was funded by the Wellcome Trust, the National Institute for Health Research, NHS England, NHS Research Scotland Scottish Senior Clinical Fellowship, Medical Research Council, Chief Scientist Office, and the Central and North West London NHS Trust.
Luchenski S, Maguire N, Aldridge RW, et al. What works in inclusion health: overview of effective interventions for marginalised and excluded populations. Lancet. 2018;391:266–80.
NICE. Community engagement: improving health and wellbeing and reducing health inequalities. NG44. London: National Institute for Health and Care Excellence; 2016.
NICE. Physical health of people in prison. NG57. London: National Institute for Health and Care Excellence; 2016.
NICE. Mental health of adults in contact with the criminal justice system. NG66. London: National Institute for Health and Care Excellence; 2017.
Public Health England. Homelessness: applying All Our Health. London: Public Health England; updated 2016.
Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre