Cognitive Health in Ageing Register: Investigational and Observational Trial Studies in Dementia Research (CHARIOT): Prospective Readiness Cohort (PRO) Longitudinal Study

Alzheimer's disease is a degenerative condition affecting the brain and is the most frequent form of dementia in older adults. Dementia is currently a major healthcare issue in the UK, affecting approximately a million people. The progression of the disease varies between individuals and the early stages may be characterised by only minimal changes in memory and thinking. These changes could remain undetected as the symptoms may be mistakenly regarded as normal age-related forgetfulness. However, dementia is not part of the normal ageing process. The disease process is now known to start at least 20 years prior to the emergence of symptoms. A protein called amyloid starts to deposit in the brain, forming clumps referred to as 'plaques'. Another protein called tau sticks to other tau molecules inside the brain cell and forms structures called 'tangles'. These changes cause damage to the brain cells, disrupting their normal functioning, leading to inflammation and ultimately destruction of the brain cells. So far, there is no cure for Alzheimer's disease, but by better understanding the changes that occur over time in the brain, scientists can find ways of detecting and therefore diagnosing and treating the disease earlier. One way in which scientists learn about how a disease develops, is by following people unaffected by the condition over an extended period of time. The same tests and sample collections are repeated to monitor any clinical changes. These are known as longitudinal studies, and CHARIOT:PRO studies are examples of this. The CHARIOT:PRO Longitudinal Study (CPLS) is an observational study of 600 participants aged \>65 years old which aims to evaluate cognition (thinking abilities) and biomarkers (biological markers which indicate the presence of disease e.g. amyloid) over time in older adults. The participants in CPLS were all screened as part of the CHARIOT:PRO Sub-Study (CPSS1) in 2015-2017. Visit 1 will be conducted within eight weeks after the Study Entry Visit (SEV). Visits 2-7 will follow at six-monthly intervals from Visit 1. During visits, information relating to health, medication, family history of dementia, self-reported cognitive function and anthropometrics will be collected. The cognitive assessments PACC5 and RBANS will be administered along with a measure of executive function (Trail Making Test). Participants will be provided with self-reported questionnaires to be completed at each onsite visit. Blood samples will be taken once a year i.e. Month 0, 12, 24 and 36. The purpose of CPLS is to continue to build on the vital data and samples already kindly donated by participants screened for CPSS1. This will provide valuable information that will enhance understanding of the earliest stages of Alzheimer's disease before obvious symptoms start to appear. Importantly, the Investigators hope to identify predictive markers of disease, which will help doctors to select the right drugs, and develop other approaches like lifestyle guidance to prevent or delay Alzheimer's disease in the future. This study is sponsored by Imperial College London, led by the Principal Investigator Professor Lefkos Middleton and is funded by Gates Ventures.