Rates of dementia have grown across all ethnic groups, the study found
“We do not know if earlier death after dementia diagnosis is because dementia is picked up at a later stage in minority ethnic groups and therefore people decline faster, if underlying risk factors in these groups contribute to worse overall health or if there is a difference in post-diagnostic support that results in these differences.” Dr Naaheed Mukadam, senior research fellow, University College London
British people from black and south Asian backgrounds who have dementia die both younger and sooner after diagnosis than white people, according to a new study.
The study by researchers from University College London (UCL) and the London School of Hygiene and Tropical Medicine found that South Asian people die 2.97 years younger and black people 2.66 years younger than their white people with dementia.
The research, led by Dr Naaheed Mukadam, senior research fellow at UCL, was based on an analysis between 1997 and 2018 of electronic health records of 662,882 UK residents aged over 65. It is the first study to look into the incidence and prevalence of dementia, as well as age of diagnosis, survival and age of death, across white, black and south Asian ethnic groups.
Other key findings include:
According to the paper, published in the medical journal Alzheimer’s & Dementia: “The earlier age of dementia diagnosis in people of black and south Asian [origin] … may be related to the higher prevalence of some risk factors for dementia such as, in older south Asians, fewer years of education, and in both groups hypertension [high blood pressure], diabetes and obesity.”
The paper adds: “Overall, our findings show black and south Asian patients are diagnosed with dementia at a younger age and die at a younger age with dementia than white patients, losing more years of life.”
The study also found that 11.8% of over-65s have dementia, the highest figure for the prevalence of dementia in Britain found in any study so far. The researchers say the difference is due to rising life expectancy since the previous estimates were drawn up.
Mukadam said that the disparity between ethnic groups was “concerning”, adding that the researchers had been unable to pinpoint the reason for the difference: “We do not know if earlier death after dementia diagnosis is because dementia is picked up at a later stage in minority ethnic groups and therefore people decline faster, if underlying risk factors in these groups contribute to worse overall health or if there is a difference in post-diagnostic support that results in these differences.”
She said, however, that “targeted interventions” to raise awareness about the greater prevalence of certain risk factors in some ethnic minorities, and how they can affect brain health, such as diabetes among south Asians, could help prevent dementia developing.
This large-scale study has revealed some valuable insights about the extent of dementia, and the differential in survival rates between ethnic groups. This starting point will enable other researchers and clinicians to explore the reasons further and to develop methods for addressing the differential outcomes. It is also significant as a piece of research in demonstrating the potential provided by electronic health records: analysing data on this scale allows researchers to discover patterns and trends that would be impossible with paper records. The existence in the NHS of a large database of electronic records covering a wide demographic range offers exciting opportunities for future research that can pinpoint the relationship between illness, diagnosis and factors such as age, sex and ethnicity. There is also great potential for investigating co-morbidities and using genomic data alongside patient records to delve deeper into the relationship between genetics and illness.