Edland, Steven D., Division of Biostatistics, Herbert Wertheim School of Public Health and Human Longevity Science, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA; Department of Neurosciences, School of Medicine, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA and Alzheimer’s Disease Cooperative Study, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA, United States