Approved Research

Investigating the influence of multimorbidity on dementia and neuroanatomy, and the mediating role of the heart-brain axis

Lay summary

50 million individuals suffering from dementia worldwide have difficulty with memory, emotion, and problem solving abilities, and struggle with daily tasks such as planning and preparing meals. This impacts family members and caregivers of dementia patients, who dedicate time and energy to meet the needs of their loved ones. The goal of this project is to better understand dementia risk, so those at risk can be identified before symptoms appear in hopes of preventing dementia from affecting them and their families. An important risk factor for dementia is multimorbidity, defined as the coexistence of multiple chronic conditions. Multimorbidity leads to difficulties in cognitive performance in the elderly and up to 80% of individuals with dementia are multimorbid.

However, key gaps in our understanding of multimorbidity remain. It is unknown how multimorbidity affects the brain. As dementia is caused by damage to brain cells, this information is key to understanding the role of multimorbidity. Also, previous studies commonly define multimorbidity by a simple disease count, or by the presence of any two diseases. This perspective does not account for different impacts of specific diseases, their combinations, or the order in which they develop. An individual with hypertension and depression may have different brain structure and risk of dementia, and require different treatment than an individual with cardiovascular disease and osteoporosis.

This two year project aims to investigate how specific patterns of multimorbidity impact the brain and dementia. Using the UK Biobank dataset, we will identify groups of diseases which coexist and determine which groups of disease pose the greatest risk for developing dementia. We will further this analysis by taking advantage of the remarkable magnetic resonance imaging (MRI) data available in the UK Biobank. We will use MRI of the brain to assess the brain health associated with different disease groups to further our understanding of the link between multimorbidity and dementia. Finally, we will also incorporate MRI of the heart to better understand how cardiovascular function may underlie the link between multimorbidity and dementia. The result of this project will contribute important knowledge towards our current understanding of the development of dementia, and who is at most risk. Importantly, this project has relevance for a large portion of an aging population, given that multimorbidity is increasingly common with older age