Can ELSA advance dementia research into the impact of socioeconomic factors on dementia?
14 June 2019
The English Longitudinal Study of Ageing is a representative cohort of the English population in the DPUK Data Portal – it has unique data with some real potential for cross-cohort dementia research. 2002 is the year it got started, 18,000 is the number of participants, eight is the number of times they have done medical tests, and 65 is their average age now. If you are interested in dementia research and have not considered using this valuable health study yet, Dr Dorina Cadar - Senior Research Fellow in Dementia at University College London - explains why you should.
Many of us will know – tragically often through personal experience – that dementia is one of the most immediate public health challenges of our time. Research has been dominated by small clinical studies of dementia, mostly conducted in the UK and US, and the current evidence base lacks reliable national data that is vital for service planning, prediction of future needs, estimating the costs of dementia care and understanding the risk factors. As one of the biggest cohort studies available to analyse in the DPUK Data Portal, the English Longitudinal Study of Ageing (ELSA) is an important resource for dementia researchers.
ELSA is an ongoing nationally representative study of the health of thousands of men and women living in England. Like many long-term population studies used in dementia research, the participants sit memory tests and have a whole range of other medical tests too. Dementia is ascertained through a combination of self-reported physician diagnosis, as well as informant evaluations and hospital statistics (The informant questionnaire is usually administered to a family member or carer, who can evaluate the changes in the everyday cognitive function in relation to memory and intelligence). What sets ELSA apart is its insights into social factors that may be implicated in dementia – these might become ‘modifiable risk factors’ and so they’re really important to know about.
Professor Andrew Steptoe, Principal Investigator of ELSA, said:
Established in 2002, ELSA is a multi-purpose survey that is focused on advancing research and informing policy across all aspects of ageing, including health and social care, retirement and pension policy, and social and civic participation. It tracks multiple and complex characteristics of the same individuals as they move through the middle to older age.
Why ELSA is important to dementia research
ELSA offers unique insights into the key characteristics of 50+ year-olds. Importantly, it has a more detailed assessment of wealth and other socioeconomic characteristics – information on multiple individual components rather than a broad categorisation of assets – than other studies to date. In a recent investigation published in JAMA Psychiatry, I found that limited wealth in late life is associated with increased risk of dementia, independent of education. This research demonstrates the importance of socioeconomic influences on dementia incidence. They are the type of findings I hope could help inform public health strategies for dementia prevention, evidencing why socioeconomic gaps should be targeted to reduce health disparities. There is so much scope for more research in important areas like this.
A great opportunity for cross-cohort studies
Although ELSA is a demographically representative health study, the ethnicity is predominantly white and therefore, researchers interested specifically in ethnic differences are unable to investigate the effects that ethnicity might have on dementia using this cohort study alone. Combining ELSA with other population studies (DPUK collaborates with 46 others) will enable this investigation in a larger scale sample. Using big data consortiums such as DPUK enables researchers interested in specific research questions to assess a detailed investigation of socioeconomic or other common characteristics in huge samples, increasing the statistical precision of their analyses.
There are several avenues and opportunities open to the researchers interested in exploring the power of multiple cohorts for dementia research. The DPUK Data Portal brings together records of over 2 million people in a free-to-access resource, and this proves an amazing opportunity for anyone interested in finding answers to dementia prevention and uncovering disease progression. New research questions could include the direct role of biomarkers on dementia incidence, as well as the indirect effects of lifestyle behaviours, social support, isolation, loneliness or cultural engagement. Besides, there is unexplored potential in examining the mediating role of cardiovascular disease and other risk factors on cognitive ageing and dementia incidence. Through the extensive monitoring of biennial interviews and a long-term follow-up, ELSA represents an important piece in the overall jigsaw of data available through DPUK. It offers the opportunity to understand the mechanisms involved in the disease progression using a multidisciplinary and integrative approach.