Dementia is a degenerative disease that commonly prevails in the older population. About 1.3% of the United Kingdom's population has been diagnosed with dementia.
More specifically, one in 14 people above 65 years of age in the U.K. has dementia, the incidence of which increases to one in six among people who are over 80 years of age. Since people over 65 years of age are the fastest-growing age group in the U.K., the number of dementia cases will likely rise in the coming years.
Study: New cases of dementia are rising in elderly populations in Wales, UK. Image Credit: Naeblys / Shutterstock.com
Western Europe has presented mixed data regarding dementia diagnoses. For example, a reduced incidence of dementia was reported in Sweden and Germany, whereas an increase in new dementia cases has been reported in Denmark.
It is important to accurately estimate the prevalence of dementia in homogenous populations, as it is difficult to estimate the true incidence in a broader population.
Alzheimer's disease (AD) is the most common form of dementia, followed by vascular dementia (VD). Some individuals present with multiple dementia subtypes, which could be due to the overlap in the diagnosis criteria. In most cases, people experience two dementia disorders, such as AD and Parkinson's disease (PD), concurrently.
About the study
A recent Journal of the Neurological Sciences study determined how the incidence and prevalence of dementia have changed over recent decades in Wales. The overlap between diagnoses of dementia subtypes was also investigated.
Data on the Welsh population was obtained from the Secure Anonymized Information Linkage (SAIL) databank, which provides a health-related dataset using anonymized IDs.
Information about dementia diagnoses was obtained from databases of hospital admission records using the International Classification of Diseases 10th Revision (ICD10) and National Health Service (NHS) read codes. Furthermore, demographic data were collected from demographic databases.
The current study utilized data on dementia between January 1, 1999, and December 31, 2018. The Welsh Index of Multiple Deprivation (WIMD) was used to determine geographical areas with the greatest and least deprivation across multiple domains, including employment, education, income, housing, access to services, community safety, and health.
All dementia cases were extracted from databases and categorized following specific dementia subtypes, including AD, frontotemporal dementia (FTD), Huntington's disease (HD), Lewy bodies (DLB), VD, and PD.
For all individuals, the first instance of each diagnosis was considered. Individuals diagnosed with "drug-induced" or "alcohol-induced" dementia were not considered in this study. Finally, a total of 206,640 'unique' diagnoses were found.
Throughout the study period, a higher incidence of AD and VD was observed in the Welsh population. In addition, a large percentage of non-specific dementia diagnoses prevailed, followed by DLB, FTD, and HD. An increase in the incidence and prevalence rates of overall dementia occurred between 1999 and 2018.
The incidence rates of dementia augmented in older people above 70 years of age and decreased in those younger than 60 years of age. However, a significant decrease in the prevalence of dementia occurred in individuals under 40 years of age, whereas the prevalence of dementia increased in those above 50 years of age.
Although no significant difference in the incidence and prevalence of overall dementia was observed between males and females, a higher number of females living with dementia was reported.
Substantial overlap was found between dementia subtypes, particularly AD and VD, was observed, thus indicating the possibility of initial misdiagnosis favoring more common subtypes.
Assuming a linear increase in dementia incidence until 2050, the all-cause dementia incidence rate was estimated to be 6.5 for every 1,000 people in the total population. This study also predicted the incidence rate to be 23.2 for every 1,000 people over 65 years of age. However, there is a possibility of the oldest age groups plateauing, which could stabilize the incidence rates.
One of the critical limitations of the study is the datasets used ranged over twenty years, during which the criteria for the diagnosis of dementia has changed. In addition, the mortality coding practice in the U.K. changed in 2011, which led to changes in the reported cause of death. As a result of these changes, it is possible that many dementia cases were overlooked in this study.
Despite these limitations, medical records of the Welsh population indicate an increase in new dementia diagnoses in older people between 1999 and 2018. This observation is linked with aging and prolonged survival time after diagnosis.
As the elderly population in the U.K. rises, it is important to predict how dementia incidence and prevalence will continue in the future.
- Stevenson-Hoare, J., Schalkamp, A., Sandor, C., et al. (2023) New cases of dementia are rising in elderly populations in Wales, UK. Journal of the Neurological Sciences. doi:10.1016/j.jns.2023.120715