Infections and brain health in ageing populations (360G-Wellcome-225868_Z_22_Z)

The world’s population is ageing rapidly, especially in Asia and Latin America. Maintaining brain health into older age is a major challenge: depression and dementia affect 7% and 5% of adults aged over 60 years respectively. Infections are potentially important, under-recognised, modifiable contributors to poor brain health, whose effects vary across settings. My research aims to analyse relationships between infections and key components of brain health (mental health, cognitive health and sensorimotor function) in older age by applying robust causal inference methods to large, longitudinal datasets. Using a combination of electronic health records from the UK and US, harmonised longitudinal surveys from Mexico, India, the UK and US and multidimensional genetic, social and health data from UK Biobank, I will address three key research questions: \- What risks do acute infections pose to brain health in UK and US populations? \- Do relationships between infections and brain health differ in India or Mexico compared to the UK and US? \- What mediates relationships between infections and brain health? I will supplement epidemiological approaches with Mendelian randomisation and causal mediation analysis to generate fundamental insights into the infection-brain health relationship across populations, with the ultimate goal of improving brain health worldwide.