The primary goal of the study was to identify trajectories for episodic memory performance in a large and ethnically diverse sample of older adults. The secondary goals were: 1) to investigate whether socio-demographic factors and APOE genotype are predictors of age-related memory decline and 2) to investigate incident rates of dementia.
Longitudinal data on episodic memory performance was gathered from five different study cohorts: The Washington Heights-Inwood Columbia Aging Project (WHICAP), The Chicago Health and Aging Project (CHAP), The National Institute on Aging Late-Onset Alzheimer Disease Family Based Study (NIA-LOAD), The National Alzheimer's Coordinating Center (NACC) and The Rush Alzheimer’s Disease Center cohorts (ROSMAP).
Trajectories of episodic memory performance over time were estimated in a large sample of 13,037 ethnically diverse elderly (average ages 72 to 85 years) using Latent Class Mixed Models. Analysis was conducted using two samples at baseline evaluation: i) non-cognitively impaired individuals, and ii) all individuals regardless of dementia status. Two major episodic memory trajectories were estimated: 1) Stable - consisting of individuals exhibiting a constant or improved memory function, and 2) Decliner - consisting of individuals whose memory function declined. The majority of the study participants maintain their memory performance over time. Compared to those with Stable trajectory, individuals characterized as Decliners were more likely to have non-white ethnic background, fewer years of education, a higher frequency of ε4 allele at APOE gene and five times more likely to develop dementia.
This work was supported by the National Institute of Health grants: P50 AG08702-26 (ADRC), 1U01AG032984 (ADGC), NIAGADS (U24 AG041689), R01-AG04179-05 (NIA-LOAD), R01AG0372 (WHICAP), R01-AG11101, R01AG051635 (CHAP), P30AG10161, R01AG15819, R01AG17917 (ROSMAP) and K01AG051348. Additional support was provided by the Department of Defense grant GRANT12043422.Samples from the National Cell Repository for Alzheimer’s Disease (NCRAD), which receives government support under a cooperative agreement grant (U24 AG21886) awarded by the National Institute on Aging (NIA), were used in this study. We thank contributors who collected samples used in this study, as well as patients and their families, whose help and participation made this work possible.
NIA/NIH Grant U01 AG016976 funds the NACC database. NACC data are contributed by the NIA-funded ADCs: P30 AG019610 (PI Eric Reiman, MD), P30 AG013846 (PI Neil Kowall, MD), P50 AG008702 (PI Scott Small, MD), P50 AG025688 (PI Allan Levey, MD, PhD), P50 AG047266 (PI Todd Golde, MD, PhD), P30 AG010133 (PI Andrew Saykin, PsyD), P50 AG005146 (PI Marilyn Albert, PhD), P50 AG005134 (PI Bradley Hyman, MD, PhD), P50 AG016574 (PI Ronald Petersen, MD, PhD), P50 AG005138 (PI Mary Sano, PhD), P30 AG008051 (PI Thomas Wisniewski, MD), P30 AG013854 (PI M. Marsel Mesulam, MD), P30 AG008017 (PI Jeffrey Kaye, MD), P30 AG010161 (PI David Bennett, MD), P50 AG047366 (PI Victor Henderson, MD, MS), P30 AG010129 (PI Charles DeCarli, MD), P50 AG016573 (PI Frank LaFerla, PhD), P50 AG005131 (PI James Brewer, MD, PhD), P50 AG023501 (PI Bruce Miller, MD), P30 AG035982 (PI Russell Swerdlow, MD), P30 AG028383 (PI Linda Van Eldik, PhD), P30 AG053760 (PI Henry Paulson, MD, PhD), P30 AG010124 (PI John Trojanowski, MD, PhD), P50 AG005133 (PI Oscar Lopez, MD), P50 AG005142 (PI Helena Chui, MD), P30 AG012300 (PI Roger Rosenberg, MD), P30 AG049638 (PI Suzanne Craft, PhD), P50 AG005136 (PI Thomas Grabowski, MD), P50 AG033514 (PI Sanjay Asthana, MD, FRCP), P50 AG005681 (PI John Morris, MD), P50 AG047270 (PI Stephen Strittmatter, MD, PhD).