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Research Paper|Volume 13, Issue 13|pp 17080—17096

Joint trajectories of episodic memory and odor identification in older adults: patterns and predictors

Christina S. Dintica1, Miriam L. Haaksma2, Jonas K. Olofsson3, David A. Bennett4, Weili Xu1,5
  • 1Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
  • 2Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands
  • 3Gösta Ekman Laboratory, Department of Psychology, Stockholm University, Stockholm, Sweden
  • 4Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
  • 5Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, China
* Equal contribution
Received: December 10, 2020Accepted: June 23, 2021Published: July 7, 2021
https://doi.org/10.18632/aging.203280

Copyright: © 2021 Dintica et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Emerging evidence suggests that olfactory function is closely linked to memory function. The aims of this study were to assess whether olfactory and episodic memory functions follow similar age-related decline trajectories, to identify different patterns of decline, as well as predictors of the patterns.

1023 participants from the Memory and Aging Project were followed for up to 8 years with annual episodic memory and odor identification assessments. Trajectories were modelled using growth mixture models. Multivariate logistic regression was used to identify pattern predictors.

Three patterns of joint trajectories were identified; Class 1- stable average performance in both functions (n=690, 67.4%); Class 2- stable average episodic memory and declining odor identification (n=231, 22.6%); and Class 3- decline in both functions (n= 102, 10.0%). Class predictors included age, sex, APOE ε4 status, cognitive activity level and BMI. Participants in Class 3 were most likely to develop dementia.

Episodic memory and olfactory function show similar trajectories in aging. Such classification can contribute to a better understanding of the factors related to cognitive decline and dementia.