1. From the Departments of Gerontology and Geriatrics (SPM, JG, RGJW, and AJMdC) and Clinical Chemistry (MF), Leiden University Medical Center, Leiden, Netherlands; the Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands (JJ); and the Academic Section of Geriatric Medicine, University of Glasgow, Glasgow, Scotland (DJS)