©
Shutterstock
Scientists in the Department of Psychiatry, supported by the National Institute for Health and Care Research (NIHR) Oxford Health Biomedical Research Centre, also found that there were “critical time windows” when the onset of these chronic health conditions could have the greatest effect on the risk of developing dementia.
Previous research has shown that the co-existence of multiple illnesses, known as multimorbidity, increases the chances of dementia, but this study is the first to identify how the age of onset of these specific health conditions makes a difference.
The study, published in the journal Brain Communications, analysed UK Biobank electronic health data from more than 282,000 people. The researchers examined the patterns of accumulation of 46 chronic health conditions from birth to 70 years old, and found that:
- Before the age of 55, people who were diagnosed with cardiometabolic disorders, such as coronary heart disease and diabetes, had the highest risk of developing dementia in the future, compared to those diagnosed with other chronic illnesses or those without any illnesses.
- Between 55 and 70 years old, people who were diagnosed with mental health conditions such as anxiety and depression, and neurovascular conditions, such as stroke, had a two-fold increase in dementia risk compared to those without any chronic illnesses.
- The findings also point to a cumulative effect; people who sequentially accumulate cardiometabolic conditions, followed later by neurovascular and mental health disorders were at the greatest risk of dementia
Senior author, Associate Professor Sana Suri, said:
Although we knew that multimorbidity increased the risk of dementia, it was unclear which combinations of health conditions had the most impact and in what sequence.
This study has identified how specific illnesses tend to co-exist with each other, and also the critical time windows in which they could pose the greatest risk.
This highlights the importance of taking into account other pre-existing illnesses when estimating a person’s chances of developing dementia and could help inform targeted strategies to reduce the risk at certain points in the lifespan.
This study identified associations between multimorbidity and dementia risk but we need to understand more about why this happens. We also need to try to replicate the study in more diverse groups of people to ensure the results are representative of the population.”
Future studies could examine whether efforts to manage or prevent cardiovascular problems in early-to-midlife, followed by mental health and neurological disorders when people are in their fifties and sixties might reduce the risk of dementia.”