Including nearly 20,000 participants, the largest study on amyloid prevalence to date estimates that a third of cognitively normal people older than 70 have amyloid building up in their brains. Published January 31 in JAMA Neurology and led by Olin Janssen and Willemijn Jansen at Maastricht University in the Netherlands, the meta-analysis compiled amyloid PET and cerebrospinal fluid (CSF)...