Blood donors provide a unique opportunity to study health and disease in the general population. This project explores how blood samples can help identify early signs of Alzheimer’s disease and Lewy body dementia. By analyzing specific blood markers, I aim to detect changes long before symptoms develop, improving diagnosis and enabling earlier interventions to potentially slow disease progression. These findings will help us use biomarkers to make better decisions about people’s health. Building on my work in neurodegenerative disease mechanisms, including clinical studies and advanced brain imaging, this project combines these approaches with donor biobank samples and cutting-edge biochemical technologies. The long follow-up period, multiple early blood samples, and nationwide coverage create a unique opportunity to study preclinical changes. With recent advancements in therapies and blood-based biomarkers, the timing is ideal for this project.