There is plenty of data to tell us how dementia impacts populations. We know that globally there are about 50m people living with the condition, and this is predicted to triple to 153m by the year 2050.1 Similarly, in the UK, cases of dementia are projected to rise rapidly.2 Research suggests that 1 in 3 people born today will develop dementia in their lifetime.3
These numbers alone, however, do not reveal the true impact of dementia on society. To understand this, we need to consider the role of health inequalities. There is evidence that certain subgroups of the population have a higher risk of developing dementia than others.4–6 Age is the most important risk factor, with the chance of developing dementia increasing to one in three over the age of 90 (although dementia affects younger people too: in the UK there are over 42,000 people with early-onset dementia, which is highly heritable).6–9 Innate characteristics like sex and ethnicity also play an important role in determining dementia risk: more women die of dementia than men (for reasons more complex than women simply living longer)10 and dementia appears to be more prevalent in Black and South Asian ethnic groups than white populations.5,6 Prevalence also increases among people with intellectual disabilities such as Down syndrome and symptoms appear earlier in these groups11,12. Finally, dementia risk is increased by certain environmental and lifestyle factors, such as air pollution or lack of physical activity, many of which are linked to socio-economic status.13,14
Research has a critical role to play in understanding – and ultimately tackling – health disparities in dementia. As we race to develop new treatments for these devastating diseases, we need to be sure that those treatments will help those who need them most. We also need to understand what puts certain groups at higher risk, and how best to prevent disease. To achieve that, we need to ask the right scientific questions and interrogate how and why different groups are affected differently by the same diseases. This requires us to reject longstanding biases in scientific research, and instead innovate in the name of inclusivity.
The UK DRI is committed to doing this in five ways:
1. Ensuring biological diversity in our science
Neuroscientists have long been aware of structural and functional differences between male and female brains,15,16 and there is now some evidence that the disease pathways of neurodegenerative diseases vary by ethnicity.17 Despite these biological differences, it has historically been considered too challenging to incorporate diversity into scientific study designs.
UK DRI scientists are changing this by incorporating biological diversity into their research. From mouse models to large-scale genetic association studies, we are working to understand the nuances of the biological pathways of disease in different sub-groups of the population, and the role played by biological factors like sex and ethnicity.
2. Innovating to diversify clinical trials
Clinical trials provide critical evidence for the safety and efficacy of new drugs in humans, and are essential for the development of future therapies. To produce generalisable results – and avoid approving drugs that are less effective or less safe in certain populations – trial participants must be representative. However, historically this has not been the case, with, for example, ethnic minorities underrepresented.18 19 In dementia, women are underrepresented in trials, despite the increased prevalence of disease.20,21
Researchers in the UK DRI are working to address challenges of trial design, resources, trust, information and geographical distance in order to widen the accessibility of our clinical trials to a wider section of our society. This includes new protocols to improve access to a diagnosis, working with community groups to widen participation, and developing an inclusive, innovative platform trial in motor neuron disease.
3. Pioneering accessible new therapies
Any new therapy developed by our scientists needs to be practical and affordable to implement. To confront health inequalities in dementia, it is essential that we consider the accessibility, scalability and affordability of our innovations while they are in development.
Dr Nir Grossman (UK DRI Group Leader at Imperial) is pioneering a non-invasive deep brain stimulation therapy, with the potential to be a new and innovative treatment for Alzheimer’s disease. After proving the concept in the lab, Grossman and his team ran a series of participant workshops to explore usability and acceptability of the device, and are subsequently re-engineering the technology to make it suitable for treatment at home. Grossman believes this is the only way to make the treatment truly accessible.
4. Addressing rare and under-researched forms of dementia
Rarer forms of dementia, or those that only affect certain groups of the population, are typically under-recognised and under-researched compared to more common forms such as Alzheimer’s disease.
UK DRI scientists are working to support people living with these rare forms of dementia right now, and to fill the knowledge gap of these diseases so that we can find new therapies in the future. This includes a major worldwide genome study on early-onset Alzheimer’s disease, and research into Alzheimer’s disease in individuals with Down syndrome (DS).
5. Exposing the impact of social inequality on brain health
Prevention is crucial to reducing health inequalities in dementia, since many of the known risk factors are socially patterned, meaning that individuals who are disadvantaged in society may also have a higher risk of becoming ill.13 At the UK DRI, our researchers are studying the environmental and lifestyle factors that increase our risk of disease – from cardiovascular health to air pollution – so that we can target preventative interventions where they will be most effective.
For more information on these research projects and many more, please read our report, “Diversity and Dementia: How is research reducing health disparities?”
1. Nichols, E. et al. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. Lancet Public Health 7, e105–e125 (2022).
2. LSE. Projections of older people with dementia and costs of dementia care in the United Kingdom, 2019–2040. www.modem-dementia.org.uk (2019).
3. Lewis, F. Estimation of Future Cases of Dementia from Those Born in 2015. https://www.ohe.org/publicatio... (2015).
4. Alzheimer’s Research UK. Prevalence - Dementia Statistics Hub. https://www.dementiastatistics.org/statistics-about-dementia/prevalence-2/.
5. Bothongo, P. L. K. et al. Dementia risk in a diverse population: A single-region nested case-control study in the East End of London. (2022) doi:10.1016/j.
6. UK Health Security Agency. Health Matters: Health inequalities and dementia. https://ukhsa.blog.gov.uk/2016... (2016).
7. Alzheimer’s Research UK. Prevalence by age in the UK - Dementia Statistics Hub. https://www.dementiastatistics.org/statistics/prevalence-by-age-in-the-uk/.
8. Alzheimer’s Society. Young-onset dementia. https://www.alzheimers.org.uk/about-dementia/types-dementia/young-onset-dementia.
9. Alzheimer’s Society. What can increase a person’s risk of dementia? https://www.alzheimers.org.uk/about-dementia/risk-factors-and-prevention/what-can-increase-persons-risk-of-dementia.
10. Alzheimer’s Research UK. The Impact of Dementia on Women. https://www.alzheimersresearch... (2022).
11. Fortea, J. et al. Alzheimer’s disease associated with Down syndrome: a genetic form of dementia. Lancet Neurol 20, 930–942 (2021).
12. Down Syndrome Medical Interest Group. Demography. https://www.dsmig.org.uk/information-resources/by-topic/demography/.
13. Rosengren, A. et al. Socioeconomic status and risk of cardiovascular disease in 20 low-income, middle-income, and high-income countries: the Prospective Urban Rural Epidemiologic (PURE) study. Lancet Glob Health 7, e748–e760 (2019).
14. Committee on the Medical Effects of Air Pollutants. Cognitive decline, dementia and air pollution. (2022).
15. Hines, M. Neuroscience and Sex/Gender: Looking Back and Forward. Journal of Neuroscience 40, 37–43 (2020).
16. Becker, J. B., Prendergast, B. J. & Liang, J. W. Female rats are not more variable than male rats: A meta-analysis of neuroscience studies. Biol Sex Differ 7, 1–7 (2016).
17. Kunkle, B. W. et al. Novel Alzheimer Disease Risk Loci and Pathways in African American Individuals Using the African Genome Resources Panel: A Meta-analysis. JAMA Neurol 78, 102–113 (2021).
18. Clark, L. T. et al. Increasing Diversity in Clinical Trials: Overcoming Critical Barriers. Curr Probl Cardiol 44, 148–172 (2019).
19. Etti, M. et al. Ethnic minority and migrant underrepresentation in Covid-19 research: Causes and solutions. EClinicalMedicine 36, (2021).
20. Steinberg, J. R. et al. Analysis of Female Enrollment and Participant Sex by Burden of Disease in US Clinical Trials Between 2000 and 2020. JAMA Netw Open 4, (2021).
21. Abdelnour, C. et al. How gender and sex influence clinical trial recruitment in Alzheimer’s disease: Findings from Fundació ACE Barcelona Alzheimer Treatment and Research Center. Alzheimer’s & Dementia 16, e041772 (2020).
Statement published June 2023
Banner image courtesy of the Centre for Ageing Better
