Cargando…

Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial

BACKGROUND: Emerging research suggests that increasing physical activity can help improve cognition among breast cancer survivors. However, little is known about the mechanism through which physical activity impacts cancer survivors’ cognition. OBJECTIVE: The objective of this secondary analysis exa...

Descripción completa

Detalles Bibliográficos
Autores principales: Hartman, Sheri J, Weiner, Lauren S, Nelson, Sandahl H, Natarajan, Loki, Patterson, Ruth E, Palmer, Barton W, Parker, Barbara A, Sears, Dorothy D
Formato: Online Artículo Texto
Lenguaje:English
Publicado: JMIR Publications 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914286/
https://www.ncbi.nlm.nih.gov/pubmed/31605514
http://dx.doi.org/10.2196/13150
_version_ 1783479780174200832
author Hartman, Sheri J
Weiner, Lauren S
Nelson, Sandahl H
Natarajan, Loki
Patterson, Ruth E
Palmer, Barton W
Parker, Barbara A
Sears, Dorothy D
author_facet Hartman, Sheri J
Weiner, Lauren S
Nelson, Sandahl H
Natarajan, Loki
Patterson, Ruth E
Palmer, Barton W
Parker, Barbara A
Sears, Dorothy D
author_sort Hartman, Sheri J
collection PubMed
description BACKGROUND: Emerging research suggests that increasing physical activity can help improve cognition among breast cancer survivors. However, little is known about the mechanism through which physical activity impacts cancer survivors’ cognition. OBJECTIVE: The objective of this secondary analysis examined physical and psychological function potentially linking physical activity with changes in cognition among breast cancer survivors in a randomized controlled trial where the exercise arm had greater improvements in cognition than the control arm. METHODS: A total of 87 sedentary breast cancer survivors were randomized to a 12-week physical activity intervention (n=43) or control condition (n=44). Objectively measured processing speed (National Institutes of Health Toolbox Oral Symbol Digit), self-reported cognition (patient-reported outcomes measurement information system [PROMIS] cognitive abilities), PROMIS measures of physical and psychological function (depression, anxiety, fatigue, and physical functioning), and plasma biomarkers (brain-derived neurotrophic factor, homeostatic model assessment 2 of insulin resistance, and C-reactive protein [CRP]) were collected at baseline and 12 weeks. Linear mixed-effects models tested intervention effects on changes in physical and psychological function variables and biomarkers. Bootstrapping was used to assess mediation. Exploratory analyses examined self-reported cognitive abilities and processing speed as mediators of the intervention effect on physical functioning. RESULTS: Participants in the exercise arm had significantly greater improvements in physical functioning (beta=1.23; 95% CI 2.42 to 0.03; P=.049) and reductions in anxiety (beta=−1.50; 95% CI −0.07 to −2.94; P=.04) than those in the control arm. Anxiety significantly mediated the intervention effect on cognitive abilities (bootstrap 95% CI −1.96 to −0.06), whereas physical functioning did not (bootstrap 95% CI −1.12 to 0.10). Neither anxiety (bootstrap 95% CI −1.18 to 0.74) nor physical functioning (bootstrap 95% CI −2.34 to 0.15) mediated the intervention effect on processing speed. Of the biomarkers, only CRP had greater changes in the exercise arm than the control arm (beta=.253; 95% CI −0.04 to 0.57; P=.09), but CRP was not associated with cognition; therefore, none of the biomarker measures mediated the intervention effect on cognition. Neither cognitive abilities (bootstrap 95% CI −0.06 to 0.68) nor processing speed (bootstrap 95% CI −0.15 to 0.63) mediated the intervention effect on physical function. CONCLUSIONS: Physical activity interventions may improve self-reported cognition by decreasing anxiety. If supported by larger studies, reducing anxiety may be an important target for improving self-reported cognition among cancer survivors. TRIAL REGISTRATION: ClinicalTrials.gov NCT02332876; https://clinicaltrials.gov/ct2/show/NCT02332876
format Online
Article
Text
id pubmed-6914286
institution National Center for Biotechnology Information
language English
publishDate 2019
publisher JMIR Publications
record_format MEDLINE/PubMed
spelling pubmed-69142862020-01-02 Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial Hartman, Sheri J Weiner, Lauren S Nelson, Sandahl H Natarajan, Loki Patterson, Ruth E Palmer, Barton W Parker, Barbara A Sears, Dorothy D JMIR Cancer Original Paper BACKGROUND: Emerging research suggests that increasing physical activity can help improve cognition among breast cancer survivors. However, little is known about the mechanism through which physical activity impacts cancer survivors’ cognition. OBJECTIVE: The objective of this secondary analysis examined physical and psychological function potentially linking physical activity with changes in cognition among breast cancer survivors in a randomized controlled trial where the exercise arm had greater improvements in cognition than the control arm. METHODS: A total of 87 sedentary breast cancer survivors were randomized to a 12-week physical activity intervention (n=43) or control condition (n=44). Objectively measured processing speed (National Institutes of Health Toolbox Oral Symbol Digit), self-reported cognition (patient-reported outcomes measurement information system [PROMIS] cognitive abilities), PROMIS measures of physical and psychological function (depression, anxiety, fatigue, and physical functioning), and plasma biomarkers (brain-derived neurotrophic factor, homeostatic model assessment 2 of insulin resistance, and C-reactive protein [CRP]) were collected at baseline and 12 weeks. Linear mixed-effects models tested intervention effects on changes in physical and psychological function variables and biomarkers. Bootstrapping was used to assess mediation. Exploratory analyses examined self-reported cognitive abilities and processing speed as mediators of the intervention effect on physical functioning. RESULTS: Participants in the exercise arm had significantly greater improvements in physical functioning (beta=1.23; 95% CI 2.42 to 0.03; P=.049) and reductions in anxiety (beta=−1.50; 95% CI −0.07 to −2.94; P=.04) than those in the control arm. Anxiety significantly mediated the intervention effect on cognitive abilities (bootstrap 95% CI −1.96 to −0.06), whereas physical functioning did not (bootstrap 95% CI −1.12 to 0.10). Neither anxiety (bootstrap 95% CI −1.18 to 0.74) nor physical functioning (bootstrap 95% CI −2.34 to 0.15) mediated the intervention effect on processing speed. Of the biomarkers, only CRP had greater changes in the exercise arm than the control arm (beta=.253; 95% CI −0.04 to 0.57; P=.09), but CRP was not associated with cognition; therefore, none of the biomarker measures mediated the intervention effect on cognition. Neither cognitive abilities (bootstrap 95% CI −0.06 to 0.68) nor processing speed (bootstrap 95% CI −0.15 to 0.63) mediated the intervention effect on physical function. CONCLUSIONS: Physical activity interventions may improve self-reported cognition by decreasing anxiety. If supported by larger studies, reducing anxiety may be an important target for improving self-reported cognition among cancer survivors. TRIAL REGISTRATION: ClinicalTrials.gov NCT02332876; https://clinicaltrials.gov/ct2/show/NCT02332876 JMIR Publications 2019-10-11 /pmc/articles/PMC6914286/ /pubmed/31605514 http://dx.doi.org/10.2196/13150 Text en ©Sheri J J Hartman, Lauren S Weiner, Sandahl H Nelson, Loki Natarajan, Ruth E Patterson, Barton W Palmer, Barbara A Parker, Dorothy D Sears. Originally published in JMIR Cancer (http://cancer.jmir.org), 11.10.2019. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Cancer, is properly cited. The complete bibliographic information, a link to the original publication on http://cancer.jmir.org/, as well as this copyright and license information must be included.
spellingShingle Original Paper
Hartman, Sheri J
Weiner, Lauren S
Nelson, Sandahl H
Natarajan, Loki
Patterson, Ruth E
Palmer, Barton W
Parker, Barbara A
Sears, Dorothy D
Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial
title Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial
title_full Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial
title_fullStr Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial
title_full_unstemmed Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial
title_short Mediators of a Physical Activity Intervention on Cognition in Breast Cancer Survivors: Evidence From a Randomized Controlled Trial
title_sort mediators of a physical activity intervention on cognition in breast cancer survivors: evidence from a randomized controlled trial
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914286/
https://www.ncbi.nlm.nih.gov/pubmed/31605514
http://dx.doi.org/10.2196/13150
work_keys_str_mv AT hartmansherij mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT weinerlaurens mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT nelsonsandahlh mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT natarajanloki mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT pattersonruthe mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT palmerbartonw mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT parkerbarbaraa mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial
AT searsdorothyd mediatorsofaphysicalactivityinterventiononcognitioninbreastcancersurvivorsevidencefromarandomizedcontrolledtrial