A Bibliometric Review on Gut Microbiome and Alzheimer's Disease Between 2012 and 2021

Abstract

Research on the microbiome has drawn an increasing amount of attention over the past decade. Even more so for its association with disease. Neurodegenerative diseases, such as Alzheimer's disease (AD) have been a subject of study for a long time with slow success in improving diagnostic accuracy or identifying a possibility for treatment. In this work, we analyze past and current research on microbiome and its positive impact on AD treatment and diagnosis. We present a bibliometric analysis from 2012 to 2021 with data retrieved on September 2, 2021, from the Scopus database. The query includes "Gut AND (Microbiota OR Microbiome) AND Alzheimer*" within the article title, abstract, and keywords for all kinds of documents in the database. Compared with 2016, the number of publications (NPs) on the subject doubled by 2017. Moreover, we observe an exponential growth through 2020, and with the data presented, it is almost certain that it will continue this trend and grow even further in the upcoming years. We identify key journals interested in the subject and discuss the articles with most citations, analyzing trends and topics for future research, such as the ability to diagnose the disease and complement the cognitive test with other clinical biomarkers. According to the test, mild cognitive impairment (MCI) is normally considered an initial stage for AD. This test, combined with the role of the gut microbiome in early stages of the disease, may improve the diagnostic accuracy. Based on our findings, there is emerging evidence that microbiota, perhaps more specifically gut microbiota, plays a key role in the pathogenesis of diseases, such as AD.

Keywords: Alzheimer’s disease; bibliometric analysis; gut microbiome; gut microbiota; microbiota-gut-brain axis; trend topics.

FIGURE 1

The PRISMA 2020 statement.

FIGURE 2

Year-wise distribution of the Scopus documents in 2012–2021.

FIGURE 3

Estimation of publications by year on gut microbiome and AD.

FIGURE 4

Number of publications per country based on affiliation.

FIGURE 5

International collaboration by country. Classification goes as multiple country publications (MCPs) in red and at a higher frequency, single country publications (SCPs) in blue.

FIGURE 6

International collaborations among countries. The pink color line represents the connection between countries and its thickness identifies the degree of collaboration. The thicker the line the stronger the collaboration rate.

FIGURE 7

Trending topics. On the x-axis, we have the time span in years, on the y-axis, the list of trending topics. The size of the circle indicates the frequency of the term, the position of the circle marks the year with most publications on that topic, and the line defines how long that term has been present.

FIGURE 8

Conceptual structure map. We observe two clusters, the one related with mouse models on the relationship between the gut microbiome and AD, and the other that studies the gut microbiome composition and dysbiosis with or without the impact of other methods in humans like probiotic agents for the restoration of cognition and reduction of amyloid-β fragments.