Wen NN, Sun LW, Geng Q, Zheng GH. Gut microbiota changes associated with frailty in older adults: A systematic review of observational studies. World J Clin Cases 2024; 12(35): 6815-6825 [DOI: 10.12998/wjcc.v12.i35.6815]
Corresponding Author of This Article
Guo-Hua Zheng, PhD, Professor, College of Nursing and Health Management, Shanghai University of Medicine and Health Sciences, No. 279 Zhouzhu Road, Pudong New District, Shanghai 201318, China. zhenggh@sumhs.edu.cn
Research Domain of This Article
Biology
Article-Type of This Article
Systematic Reviews
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Clin Cases. Dec 16, 2024; 12(35): 6815-6825 Published online Dec 16, 2024. doi: 10.12998/wjcc.v12.i35.6815
Gut microbiota changes associated with frailty in older adults: A systematic review of observational studies
Na-Na Wen, Li-Wei Sun, Qian Geng, Guo-Hua Zheng
Na-Na Wen, Li-Wei Sun, Qian Geng, Guo-Hua Zheng, College of Nursing and Health Management, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China
Na-Na Wen, Graduate School, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
Author contributions: Wen NN was responsible for conceptualization, literature screening, data curation, extraction, methodology and writing original draft; Sun LW and Geng Q were responsible for literature screening, data curation, extraction and methodology; Zheng GH was responsible for conceptualization, methodology, project administration, supervision, writing original draft, writing review, and editing; all of the authors read and approved the final version of the manuscript to be published.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Guo-Hua Zheng, PhD, Professor, College of Nursing and Health Management, Shanghai University of Medicine and Health Sciences, No. 279 Zhouzhu Road, Pudong New District, Shanghai 201318, China. zhenggh@sumhs.edu.cn
Received: August 15, 2024 Revised: September 4, 2024 Accepted: September 25, 2024 Published online: December 16, 2024 Processing time: 70 Days and 1.7 Hours
Abstract
BACKGROUND
Frailty is a complex aging-related syndrome characterized by a cumulative loss of physiological reserve and increased vulnerability to adverse clinical outcomes, including falls, disability, incapacity and death. While an increasing number of studies suggest that the gut microbiota may play a key role in the pathophysiology of frailty, direct evaluation of the association between gut microbiome alterations and frailty in older adults remains limited.
AIM
To gain insight into gut dysbiosis in frail older adults.
METHODS
Seven electronic databases (China National Knowledge Infrastructure, VIP, SinoMed, Wanfang, PubMed, Web of Science and EMBASE) were searched for articles published before October 31, 2023 to identify observational studies that compared the microbiomes of older adults with and without frailty. The diversity and composition of the gut microbiota were the main outcomes used to analyze the associations of changes in the gut microbiota with frailty in older adults. The quality of the included studies was assessed via the Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality.
RESULTS
Eleven observational studies with 912 older adults were included in this review. Consistent results revealed a significant difference in the gut microbiota composition between frail and non-frail older adults, with a significant decrease in α diversity and a significant increase in β diversity in frail older adults. The pooled results revealed that at the phylum level, four microbiota (Actinobacteria, Proteobacteria, Verrucomicrobia and Synergistetes) were significantly enriched, and two microbiota (Firmicutes and Fusobacteria) were significantly depleted in frail older adults. At the family level, the results consistently revealed that the abundances of 6 families, most of which belong to the Actinobacteria or Proteobacteria phylum, were greater in frail than in non-frail older adults. At the genus or species level, consistent results from more than two studies revealed that the abundances of the genera Prevotella, Faecalibacterium, and Roseburia were significantly lower in frail older adults; individual studies revealed that the abundances of some genera or species (e.g., Megamonas, Blautia, and Megasphaera) were significantly lower, whereas those of other genera or species (e.g., Bifidobacterium, Oscillospira, Ruminococcus and Pyramidobacter) were significantly greater in frail older adults.
CONCLUSION
This systematic review suggests that changes in the gut microbiota are associated with frailty in older adults, which is commonly reflected by a reduction in beneficial species and an increase in pathogenic species. However, further studies are needed to confirm these findings.
Core Tip: A growing number of studies have reported changes in the composition and diversity of the gut microbiota between frail and healthy older adults, suggesting that alterations in the gut microbiota may play a key role in the pathophysiology of frailty; however, direct assessment of the associations between changes in the gut microbiome and frailty in older adults remains limited. This review revealed a significant decrease in α diversity and a significant increase in β diversity in frail older adults compared with non-frail older adults, which was commonly reflected by a reduction in beneficial species and an increase in pathogenic species. This study provides a comprehensive overview of the relationship between changes in the gut microbiota and frailty in older adults and suggests a possible role for the gut microbiota in the pathogenesis of frailty.
