Alzheimer's disease is the most common form of dementia, and scientists so far have been unable to find a treatment to stop its progression in people who already have some mental decline.
So two large studies are starting much earlier, trying to prevent the disease by targeting the very first brain changes while memory and thinking skills are still intact.
To participate, people must first join GeneMatch, a confidential registry of older people who will be tested to see if they carry a gene that raises their risk for Alzheimer's.
Banner Alzheimer's Institute in Phoenix is leading the work, and clinics throughout the United States and some other countries are signing up participants.
