Researchers based in the capital will join forces with colleagues from Spain and Sweden to lead the brain imaging project - known as the TriBEKa Consortium.
The team hopes it will be able to paint the clearest picture yet of the first factors that determine risk of dementia.
Although the condition is associated with old age, changes in the brain that lead to dementia can occur decades before symptoms appear.
Experts say that understanding these changes are key to developing ways to intervene before irreversible damage has been done.
Dementia is an umbrella term for a set of symptoms, including impaired thinking and memory, that can be caused by issues other than Alzheimer’s such as Huntington’s disease and Parkinson’s disease.
Deaths in Scotland from Alzheimer’s disease rose by 10.5 per cent last year to 1,963, despite a 10 per cent fall in other dementia-related deaths to 3,603, according to official figures.
The consortium - the largest of its type to focus on this age group - brings together experts led by the University of Edinburgh, the BarcelonaBeta Brain Research Centre in Spain and Sweden’s Karolinska Institute.
Researchers will use a brain scanning technique known as positron emission tomography (PET) to detect harmful build-up of chemicals associated with dementia. Brain structure will be measured using a tool known as magnetic resonance imaging (MRI).
Participants in the study - aged between 40 and 65 - will also take part in memory tests, family history and lifestyle assessments and will be invited to take part in a three-year follow-up.
Data gathered from the project will be made available to the global science community using data-sharing platform known as the Global Alzheimer’s Association Interactive Network (GAAIN).
The funding boost comes from the US-based Alzheimer’s Association and donation from an anonymous international charitable foundation. The project will be launched on Friday in London at the Alzheimer’s Association International Conference.
Dementia affects 47 million people worldwide, with Alzheimer’s disease the most common cause. There are 9.9 million new cases diagnosed globally each year.
Professor Craig Ritchie, director of the University of Edinburgh’s centre for dementia prevention, said: “Dementia is an urgent health issue and requires forward-thinking international collaboration to defeat it. As brain changes that cause dementia happen many years before symptoms, we have an opportunity to prevent progression before people are affected. TriBEKa puts us in a unique position to understand how we might do this.”
There are around 90,000 people living with dementia in Scotland and it is estimated that 20,000 people will be diagnosed with the condition each year by 2020.
Dr Maria C. Carrillo, chief science officer at the Alzheimer’s Association, said: “We are proud to contribute the TriBEKa Consortium. We know that it is essential that we learn how to identify Alzheimer’s brain changes at the earliest point, with the goal of understanding risk factors to ultimately intervening in the disease process before cognitive decline and dementia symptoms are present.”