Bibliometric analysis reveals research trends connecting Alzheimer's disease and the gut microbiome

By Dr. Priyom Bose, Ph.D.Jul 25 2023Reviewed by Benedette Cuffari, M.Sc.

Alzheimer’s disease (AD) is a neurodegenerative disorder that is primarily diagnosed in the elderly. Although AD is prevalent throughout the world, the exact cause and underlying mechanisms responsible for this disease remain unclear.

A recent Nutrients study utilizes bibliometric analysis of published research to investigate the relationship between the gut microbiome and AD pathogenesis.

Study: Mapping Research Trends and Hotspots in the Link between Alzheimer’s Disease and Gut Microbes over the Past Decade: A Bibliometric Analysis. Image Credit: Corona Borealis Studio / Shutterstock.com

Background

The human gut microbiome is involved with many physiological processes, including those affecting the central nervous system (CNS), immune system, and endocrine system. Although the gut microbiome is a possible contributor to AD pathophysiology, the exact etiology remains unclear.

The microbiota-gut-brain axis has been established to be the key communication network that connects the CNS with the gut microbiota, which influences the progression and manifestation of AD. Gut microbial dysbiosis affects neuroinflammation and neurodegeneration, both of which are key factors in AD pathogenesis. There is a need for more research to understand better the complexities of the relationship between the microbiota-gut-brain axis and AD’s pathogenesis.

Bibliometric analysis is an invaluable tool, as it can highlight academic progress based on the contributions and interplay among various research components. Although a vast body of research on gut microbiota and AD is available, there remains a lack of a comprehensive understanding of the overall research trend and key focus areas in this field.

About the study

The current study utilized bibliometric analysis to map research trends and identify hotspots linked to AD and the gut microbiome. Herein, the researchers aimed to provide important insights into the dynamic trends, intellectual structure, and prospective hotspots in this domain, which will help guide future research in the right direction.

All relevant studies were obtained from the Web of Science Core Collection (WoSCC) from its inception until February 23, 2023.

Study findings

A total of 1,170 studies were obtained between 2012 and 2022. Notably, there has been a surge in research related to this field since 2014, which could be due to progress in research tools and techniques. These scientific advancements enabled a detailed exploration of the gut microbiome to establish the link between gut health and neurological conditions.

A total of 67 countries throughout the world, including the United States, China, Germany, Italy, Canada, Japan, Spain, Australia, and the United Kingdom, have contributed to this field of research. This indicates a global interest in research related to AD and the gut microbiome.

Among all countries, China and the U.S. have contributed the most to the publications. Both these countries have heavily invested in this field of research, possibly due to the high prevalence of AD. 

Scientists from varied regions have collaborated to study the link between AD and the gut microbiome. The majority of scientific collaborations related to this research field were found between China and the U.S., followed by the U.S. with Canada and Ireland.

Although the top three contributors of, China, the U.S., and Italy have similar amounts of publications on gut microbiota and AD, the U.S. leads in terms of citation count. This indicates that research in this field conducted by the U.S. is particularly ground-breaking.

Based on the Multiple Country Publication (MCP) ratio, Canada exhibited the highest tendency towards international collaboration in their research efforts. In contrast, South Korea had the lowest MCP ratio, which indicated their inclination towards domestic collaborations.

The three most productive journals in this research field were identified as the Journal of Alzheimer’s Disease, Nutrients, and the International Journal of Molecular Science. Nevertheless, many other journals publish research concerning AD and gut microbiome. The interdisciplinary nature of this research field allows it to be published in various journals with different research focuses. 

The Shanghai Jiaotong University has been a significant contributor to the field of gut microbiota and AD, as it accounts for about 5.1% of the total publications considered in this study. Notably, the Chinese Academy of Sciences and Harvard Medical School have established broad collaborations in this field. The most cited study was published in 2019 and titled “The Microbiota-Gut-Brain Axis.”

A hotspot analysis revealed the most frequent mention of oxidative stress and neuroinflammation related to gut microbiota and AD. There has been a shift in research focus, where independent researchers are more interested in analyzing the influence of short-chain fatty acids (SCFA) on AD; however, more studies are needed to validate their effect on disease prognosis.

Conclusions

In the past decade, research linked to gut microbiota and AD is progressing rapidly. Recent studies are more focused on determining the role of SCFA, gut-brain axis, neuroinflammation, and oxidative stress in AD. Notably, the emerging gut microbial targeted therapy has shown significant promise to combat AD.