Differential effects of APOE and modifiable risk factors on hippocampal volume loss and memory decline in Aβ- and Aβ+ older adults
Author Identifier
Simon M. Laws
https://orcid.org/0000-0002-4355-7082
Ralph N. Martins
https://orcid.org/0000-0002-4828-9363
Stephanie R. Rainey-Smith
Document Type
Journal Article
Publication Title
Nuerology
Publisher
Wolters Kluwer / American Academy of Neurology
School
School of Medical and Health Sciences / Centre for Precision Health
RAS ID
43551
Funders
National Health and Medical Research Council
Grant Number
NHMRC Numbers : APP1197315, GNT1147465, GNT1162645
Abstract
Background and Objectives This prospective study sought to determine the association of modifiable/nonmodifiable components included in the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) risk score with hippocampal volume (HV) loss and episodic memory (EM) decline in cognitively normal (CN) older adults classified as brain β-amyloid (Aβ) negative (Aβ−) or positive (Aβ+). Methods Australian Imaging, Biomarkers and Lifestyle study participants (age 58–91 years) who completed ≥2 neuropsychological assessments and a brain Aβ PET scan (n = 592) were included in this study. We computed the CAIDE risk score (age, sex, APOE ε4 status, education, hypertension, body mass index [BMI], hypercholesterolemia, physical inactivity) and a modifiable CAIDE risk score (CAIDE-MR; education, hypertension, BMI, hypercholesterolemia, physical inactivity) for each participant. Aβ+ was classified using Centiloid >25. Linear mixed models assessed interactions between each CAIDE score, Aβ group, and time on HV loss and EM decline. Age, sex, and APOE ε4 were included as separate predictors in CAIDE-MR models to assess differential associations. Exploratory analyses examined relationships between individual modifiable risk factors and outcomes in Aβ− cognitively normal (CN) adults. Results We observed a significant Aβ group × CAIDE × time interaction on HV loss (β [SE] = –0.04 [0.01]; p < 0.000) but not EM decline (β [SE] = –2.33 [9.96]; p = 0.98). Decomposition revealed a significant CAIDE × time interaction in Aβ+ participants only. When modifiable/nonmodifiable CAIDE components were considered separately, we observed a significant Aβ group × CAIDE-MR × time interaction on EM decline only (β [SE] = 3.03 [1.18]; p = 0.01). A significant CAIDE-MR score × time interaction was observed in Aβ− participants only. Significant interactions between APOE ε4 and age × time on HV loss and EM decline were observed in both groups. Exploratory analyses in Aβ− CN participants revealed a significant interaction between BMI × time on EM decline (β [SE] = –3.30 [1.43]; p = 0.02). Discussion These results are consistent with studies showing that increasing age and APOE ε4 are associated with increased rates of HV loss and EM decline. In Aβ− CN adults, lower prevalence of modifiable cardiovascular risk factors was associated with less HV loss and EM decline over ∼10 years, suggesting interventions to reduce modifiable cardiovascular risk factors could be beneficial in this group.
DOI
10.1212/WNL.0000000000200118
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Comments
Rosenich, E., Bransby, L., Yassi, N., Fripp, J., Laws, S. M., Martins, R. N., ... & Lim, Y. Y. (2022). Differential Effects of APOE and Modifiable Risk Factors on Hippocampal Volume Loss and Memory Decline in Aβ− and Aβ+ Older Adults. Neurology, 98(17), e1704-e1715. https://doi.org/10.1212/WNL.0000000000200118