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A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain

We studied how brain volume loss in old age is affected by age, the APOE gene, sex, and the level of education completed. The quantitative characterization of brain volume loss at an old age relative to a young age requires—at least in principle—two MRI scans, one performed at a young age and one at...

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Autores principales: Gómez-Ramírez, Jaime, Fernández-Blázquez, Miguel A., González-Rosa, Javier J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9656120/
https://www.ncbi.nlm.nih.gov/pubmed/36295023
http://dx.doi.org/10.3390/life12101586
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author Gómez-Ramírez, Jaime
Fernández-Blázquez, Miguel A.
González-Rosa, Javier J.
author_facet Gómez-Ramírez, Jaime
Fernández-Blázquez, Miguel A.
González-Rosa, Javier J.
author_sort Gómez-Ramírez, Jaime
collection PubMed
description We studied how brain volume loss in old age is affected by age, the APOE gene, sex, and the level of education completed. The quantitative characterization of brain volume loss at an old age relative to a young age requires—at least in principle—two MRI scans, one performed at a young age and one at an old age. There is, however, a way to address this problem when having only one MRI scan obtained at an old age. We computed the total brain losses of elderly subjects as a ratio between the estimated brain volume and the estimated total intracranial volume. Magnetic resonance imaging (MRI) scans of 890 healthy subjects aged 70 to 85 years were assessed. A causal analysis of factors affecting brain atrophy was performed using probabilistic Bayesian modelling and the mathematics of causal inference. We found that both age and sex were causally related to brain atrophy, with women reaching an elderly age with a 1% larger brain volume relative to their intracranial volume than men. How the brain ages and the rationale for sex differences in brain volume losses during the adult lifespan are questions that need to be addressed with causal inference and empirical data. The graphical causal modelling presented here can be instrumental in understanding a puzzling scientific area of study—the biological aging of the brain.
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spelling pubmed-96561202022-11-15 A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain Gómez-Ramírez, Jaime Fernández-Blázquez, Miguel A. González-Rosa, Javier J. Life (Basel) Article We studied how brain volume loss in old age is affected by age, the APOE gene, sex, and the level of education completed. The quantitative characterization of brain volume loss at an old age relative to a young age requires—at least in principle—two MRI scans, one performed at a young age and one at an old age. There is, however, a way to address this problem when having only one MRI scan obtained at an old age. We computed the total brain losses of elderly subjects as a ratio between the estimated brain volume and the estimated total intracranial volume. Magnetic resonance imaging (MRI) scans of 890 healthy subjects aged 70 to 85 years were assessed. A causal analysis of factors affecting brain atrophy was performed using probabilistic Bayesian modelling and the mathematics of causal inference. We found that both age and sex were causally related to brain atrophy, with women reaching an elderly age with a 1% larger brain volume relative to their intracranial volume than men. How the brain ages and the rationale for sex differences in brain volume losses during the adult lifespan are questions that need to be addressed with causal inference and empirical data. The graphical causal modelling presented here can be instrumental in understanding a puzzling scientific area of study—the biological aging of the brain. MDPI 2022-10-12 /pmc/articles/PMC9656120/ /pubmed/36295023 http://dx.doi.org/10.3390/life12101586 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Gómez-Ramírez, Jaime
Fernández-Blázquez, Miguel A.
González-Rosa, Javier J.
A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain
title A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain
title_full A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain
title_fullStr A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain
title_full_unstemmed A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain
title_short A Causal Analysis of the Effect of Age and Sex Differences on Brain Atrophy in the Elderly Brain
title_sort causal analysis of the effect of age and sex differences on brain atrophy in the elderly brain
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9656120/
https://www.ncbi.nlm.nih.gov/pubmed/36295023
http://dx.doi.org/10.3390/life12101586
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