Bibliometric Insights into Research Hotspots and Trends in Obesity and Asthma from 2013 to 2023

Obesity has emerged as a critical global health concern, affecting a staggering number of individuals worldwide [1]. With over 2 billion people categorized as overweight, the prevalence of obesity has witnessed a threefold increase in more than 70 countries since 1980, and this alarming trend continues unabated [2]. The profound impact of obesity extends beyond mere aesthetics, encompassing a chronic disease that detrimentally affects virtually every organ and tissue within the body [3]. Among the various health complications associated with obesity, respiratory diseases have garnered considerable attention. Early investigations have already established a correlation between obesity and respiratory conditions, particularly asthma [4‒8]. Notably, Xanthopoulos et al. identified a noteworthy association between being overweight and experiencing respiratory symptoms of asthma [9]. Subsequent to this seminal study, numerous research endeavors have delved into exploring the intricate relationship between body mass index (BMI) and asthma [10‒19]. Despite these advancements, the precise mechanisms underlying the connection between obesity and asthma remain elusive. Hypotheses regarding inflammation, hormonal alterations, and mechanical factors have been posited, yet further investigations are warranted to unravel the complexities involved [20‒23]. Moreover, it is crucial to recognize the impact of obesity on the management and control of asthma, as evidence suggests that obese individuals often exhibit poorer asthma outcomes [24‒26].

In the realm of medical research, it is imperative to stay informed about the latest advances and emerging trends. Bibliometric analysis serves as a valuable method for quantifying and visualizing published literature, offering a comprehensive overview of the current state of research within a specific field while also identifying potential avenues for future investigation [27]. Through bibliometric analysis, one can gain insights into the characteristics, status, and evolving trends of research in a particular area, such as asthma. Remarkably, despite the high prevalence of both obesity and asthma, there is a notable dearth of bibliometric analyses focusing on the collaborative patterns, research trends, and hotspots within the intersection of these two conditions. Consequently, to address this gap and provide a clearer understanding of the existing research landscape, our study undertook a comprehensive bibliometric analysis to quantify and visualize the research output in the domain of obesity and asthma by scrutinizing published papers. By conducting this bibliometric analysis, we endeavor to shed light on the current state of research, elucidate potential areas for further exploration, and offer valuable insights to guide future studies in this crucial area of medical research.

For this study, we conducted a literature search using the Web of Science Core Collection, specifically the Science Citation Index Expanded (SCI-E) and Social Sciences Citation Index (SSCI), encompassing the period from January 1, 2013, to November 30, 2023. The search strategy employed the following terms: (TS = [“asthma” OR “bronchial asthma”]) AND (TS = [“obesity”]). The document types were restricted to articles and reviews, and only English-language publications were considered for inclusion in the analysis.

The inclusion criteria encompassed original peer-reviewed articles and reviews pertaining to obesity and asthma. We specifically focused on published literature addressing the relationship between these two conditions. Conversely, exclusion criteria involved filtering out early access articles, conference abstracts, editorial material, and other nonrelevant publications. Additionally, duplicate publications were also excluded from the analysis.

To perform a comprehensive analysis of the retrieved publications, all relevant records were downloaded in plain text format and analyzed using bibliometric methods. Specifically, VOSviewer (version 1.6.20.0, Leiden University), a software application capable of generating bibliometric maps for visualizing collaborations among countries, institutions, authors, keywords, and references, was employed [28]. The bibliometric maps generated using VOSviewer provide an effective means of identifying research trends, areas of collaboration, and key contributors in the field of interest. In the generated maps, each node corresponds to an individual author or institution, with nodes of the same color indicating membership in the same cluster. The size of the circle reflects the number or frequency of individuals, while the lines connecting the circles indicate the strength of collaboration [29]. Additionally, data statistics and analyses were performed using Microsoft Excel (version 2310) and GraphPad Prism (version 8.0) to provide a more thorough understanding of the publication landscape.

A total of 3,892 publications were initially retrieved from SCI-E and SSCI databases. Following the exclusion of duplicates, non-article, and review publications, as well as non-English publications, a final set of 3,406 publication records was identified and included in the subsequent bibliometric analysis (Fig. 1).

Over the past decade, there has been a consistent upward trend in the annual publication of papers, with the cumulative number of articles also demonstrating a general increase (Fig. 2). The majority of these publications consist of original articles and reviews (3,406/3,809, 89.42%), effectively capturing the evolving landscape of obesity and asthma research. The analysis of document types revealed that original research articles comprise the mainstream in the field of obesity and asthma research. Notably, the database search yielded 3,406 articles, which collectively garnered 101,910 citations, averaging approximately 29.92 times per article, and resulting in an H index of 131 (Fig. 3). This substantial citation count underscores the growing attention that the field of obesity and asthma has received from researchers. Furthermore, our findings indicate a decline in the global average annual number of publications and citations in scientific literature from 2021 to 2023, potentially attributed to the influence of the pandemic of coronavirus disease when compared to the preceding period.

A total of 117 countries worldwide have contributed to the scientific literature on obesity and asthma. The ten most prolific contributors to this field were the USA, China, Australia, the United Kingdom, South Korea, Italy, Brazil, Canada, Spain, and Japan, collectively accounting for 70.29% (2,394/3,406) of all publications. Notably, the United Kingdom had the highest average citation count per article (46.31), followed closely by the USA (38.19), Spain (37.62), Canada (33.70), and Australia (31.66) (refer to Table 1). This suggests that within the United Kingdom, obesity and asthma research holds significant credibility and enjoys broad recognition within academic circles. While China ranks second globally in terms of publication volume in the obesity and asthma research field, the average citation count per article of Chinese scholarship appears to be comparatively lower. This suggests a need for Chinese researchers to further enhance the quality and visibility of their research outputs in this domain. The analysis of the top 30 productive countries revealed the formation of six distinct clusters, which were visualized in a network representation. Notably, active collaboration was observed between the USA and China (Fig. 4a). Regarding the research dynamics and trends, from 2013 to 2019, a significant concentration of studies on obesity and asthma was observed in the USA, Canada, Australia, and Spain. However, after 2019, the field gradually gained more attention from other countries, indicating broader involvement and emerging research directions (Fig. 4b).

A total of 4,573 institutions were analyzed in this study through collaborative network analyses between universities and institutions. The top 100 universities/institutions were visualized as a network and overlay, resulting in the formation of six distinct clusters (Fig. 5a). Each cluster was represented by a major institution with the most articles in their respective field, including Harvard Medical School (n = 71, 2.08%, cluster 3), Johns Hopkins University (n = 71, 2.08%, group 2), University of Newcastle (n = 65, 1.91%, group 4), Karolinska Institution (n = 50, 1.47%, group 1), University of Toronto (n = 31, 0.91%, cluster 5), and Seoul National University (n = 27, 0.80%, cluster 6). The largest cluster, cluster 1, comprised 33 nodes representing various associated universities or institutions, while the smallest cluster, cluster 6, had only 3 nodes. Other clusters included 31 nodes (cluster 2), 14 nodes (cluster 3), 11 nodes (cluster 4), and 7 nodes (cluster 5). Moreover, the study findings revealed that the University of Pittsburgh, University of Newcastle, and Johns Hopkins University made significant contributions to this research field from 2013 to 2019. Subsequently, after 2019, these studies gradually spread to other institutions such as Harvard Medical School and University of California San Francisco (Fig. 5b).

In the field of interest, price, a prominent researcher, observed that a significant proportion of papers were authored by a specific group of highly productive scholars. Interestingly, the size of this group was found to be approximately equal to the square root of the total number of authors involved in the study [30]. This finding suggests that a relatively small but prolific subset of authors contributes significantly to the overall body of research on the topic. In the present study, a total of 17,347 authors contributed to the publication output within this research domain. Employing Price’s Law, we identified the top 155 most productive authors, and their author visualization maps revealed the formation of 11 distinct clusters (refer to Fig. 6). Notably, the largest cluster was associated with Erick Forno (22/17,347) from the University of Pittsburgh. Following closely, the second largest author cluster was represented by Anne Dixon (18/17,347) from the University of Vermont, Burlington, VT. Furthermore, Lisa G. Wood (15/17,347) emerged as the third most prominent cluster, displaying a prolific publication record and frequent collaborations with other researchers (Fig. 6; Table 2). Among all authors, Anne E. Dixon authored 40 papers, demonstrating the highest publication count. Erick Forno authored 30 papers, placing second, while Lisa G. Wood published 29 papers, ranking third. Table 2 highlights that all authors ranked in the top ten have published more than 20 papers, indicating their high level of activity and significant achievements in the fields of obesity and asthma.

Examining and synthesizing articles from top-ranking journals provides a clear overview of the primary sources of relevant research literature in this field, aiding researchers in efficiently conducting literature inquiries, acquiring data, and submitting papers. In our investigation, a comprehensive analysis was conducted on 1,010 journals that published articles related to obesity and asthma. The outcomes revealed the following noteworthy findings: Journal of Asthma emerged as the most productive journal with a total of 123 publications, yet its recent impact factor, total citation frequency, and citations per paper did not lead, suggesting insufficient academic influence. Enhancing the overall impact of this platform in the fields of obesity and asthma research is crucial. The Journal of Allergy and Clinical Immunology received the highest number of citation times, with a remarkable count of 2,060 times. Furthermore, American Journal of Respiratory and Critical Care Medicine demonstrated outstanding performance with an average citation of 189.17 times across six publications. Refer to online supplementary file 1 (available at https://doi.org/10.1159/000541474) for a detailed list of the top ten prolific, frequently cited, and highly cited journals.

Among the 3,406 records analyzed, Table 3 presents the top 10 most cited articles [31‒40]. The article that received the highest number of citation times is Shapouri-Moghaddam et al. [39] publication in the Journal of Cellular Physiology, titled “Macrophage plasticity, polarization, and its role in various diseases, including obesity and asthma” with a remarkable citation count of 2,164, surpassing the second-ranked paper by a significant margin (1,100 citations) [37]. Additionally, the third most cited paper focuses on the causes and treatment strategies for obesity and associated health risks, accumulating 555 citations [32].

The co-citation network of references was visually analyzed using VOSviewer, resulting in the identification of four distinct clusters comprising a total of 126,970 references (Fig. 7). Notably, larger nodes within the network represent highly cited references, while thicker lines indicate stronger co-citation relationships. Table 4 showcases the top 10 most co-cited references, which primarily appeared in esteemed journals such as the American Journal of Respiratory and Critical Care Medicine, Journal of Allergy and Clinical Immunology, Nature Medicine, and Archives of Internal Medicine [38, 41‒49].

Keywords serve as succinct indicators of pertinent features in scientific research, illuminating focal points within a discipline and their interconnections. VOSviewer was utilized to construct a keyword co-occurrence map based on high-frequency occurrences. Node size in the figure corresponds to the frequency of keyword co-occurrence, highlighting prominent topics within the research domain. In the present study, a total of 10,092 keywords were extracted from the search records and comprehensive analyses were conducted. Through network graph analysis, the top 100 keywords were classified into 5 distinct clusters, with a notable concentration of the top 10 keywords within the green cluster (Figure 8a). The most frequently occurring keywords were identified as “obesity (n = 1,799),” “asthma (n = 1,584),” “body-mass index (n = 614),” “children (n = 608)” and “risk (n = 545).” The low frequency of co-occurrence among other keywords suggests that further research is needed to delve deeper into the topic. These findings indicate an emerging research stage with promising broad implications. Furthermore, an examination of Figure 8b and Table 5 revealed that the predominant areas of research focus in obesity and asthma over the past decade encompassed BMI, pediatric population studies, inflammatory response mechanisms, and lung function assessments. These findings provide valuable insights into the prevailing research trends and thematic emphases within the domains of obesity and asthma, thereby contributing to a more comprehensive understanding of these prevalent health conditions.

Our analysis of keywords from 2022 to 2023 has yielded a list of prospective research frontiers, as detailed in Table 6. These frontiers include comorbidity of obesity and asthma, metabolism studies, Mendelian randomization, gut microbiome, inflammation response, gene, and biomarker research. Our findings demonstrate potential areas for future investigations and provide valuable guidance for researchers.

Compared to traditional literature reviews, bibliometric analyses offer a systematic approach to examining the published literature within a specific field [50]. This study presents an overview of collaborative networks, research trends, hotspots, and future directions in the realm of obesity and asthma through bibliometric analysis. A total of 3,406 records were collected from 1,010 journals, involving 17,347 authors affiliated with 4,573 institutions across 117 countries.

Our study reveals that the cumulative number of publications in this field is steadily increasing, signifying its emergence as a research hotspot. This observation underscores the potential for new researchers to explore this area and contribute novel insights to its knowledge base. A significant relationship has been observed between academic productivity and socioeconomic status across a wide range of countries [51]. The study conducted by Yao et al. [52] further highlights the strong correlation between multiple factors and the number of papers published within a specialized field, with the country’s GDP exhibiting the highest level of association. Regarding paper production, the USA holds the leading position, followed by China, Australia, the United Kingdom, and Korea. Notably, these top five countries with the highest publication rates are predominantly developed nations. Citation rate serves as a crucial metric to gauge the academic impact of a paper, effectively representing the degree to which a country’s scientific research outcomes are accepted and acknowledged by other institutions or nations [53]. The USA (n = 42,885) and the United Kingdom (n = 6,900) emerged as the leading contributors in terms of total citation frequency. Notably, the United Kingdom displayed the highest average citation frequency, indicating its significant influence within the field under investigation. Previous studies have underscored the influential role of international collaboration in fostering academic productivity in specific disciplines [54]. Our analysis revealed varying levels of collaboration among different countries and regions. As the foremost publishing nation, the USA established robust connections with China, followed closely by Australia. These nations also ranked among the top five in terms of publication output. The findings highlight regional disparities among various countries and regions, underscoring the imperative to strengthen cooperation and knowledge exchange between developed and developing nations worldwide. The analysis of institutions and authors mirrored the distribution observed across countries and regions. Out of the 4,573 research institutions evaluated in this study, Harvard Medical School, Johns Hopkins University, University of Newcastle, Karolinska Institution, University of Toronto, and Seoul National University emerged as significant contributors to the field and demonstrated stable collaborations with other teams. Notably, Anne E. Dixon stood out as the most prolific author over the past decade, publishing extensively on topics related to airway physiology, inflammatory responses, lifestyle interventions, asthma medications, and immunological research [38, 55‒60]. Her impressive publication output highlights her valuable contributions to the field.

Obesity constitutes a significant predisposing factor for asthma, yielding a higher occurrence rate among individuals with asthma in comparison to the general populace. The intricate linkages between obesity and asthma involve multiple mechanisms, resulting in diverse asthma phenotypes specifically observed in obese patients. By elucidating these pathways, a comprehensive comprehension of the intricate interplay between obesity and asthma can be achieved, thereby advancing our knowledge in this complex field [61]. The topic of asthma and its association with obesity has garnered significant attention and recognition from several journal editors. Our results indicate that hundreds of journals have published articles on this subject, with the top 10 journals contributing the most. Notably, the Journal of Asthma had the highest number of published articles, whereas the Journal of Allergy and Clinical Immunology emerged as the most cited journal. The American Journal of Respiratory and Critical Care Medicine had the highest average paper citation rate, highlighting its importance in this field. Additionally, the top 3 most cited journals with the highest average citations were all top-ranked journals, underscoring their widespread recognition by researchers in the field. The top cited records were published in the American Journal of Respiratory and Critical Care Medicine, Journal of Allergy and Clinical Immunology, Nature Medicine, and Archives of Internal Medicine. Among the 10 most cited research articles in this field, common themes included pathogenesis, epidemiology, pathophysiological features, immunology, diagnosis, and treatment of asthma in relation to obesity. Co-citation analysis of the references revealed significant contributions to the field from studies focusing on “phenotypes,” “airway hyperresponsiveness,” and “inflammation,” thereby providing valuable guidance for researchers who are new to this field [43‒45, 48].

High-frequency keywords serve as effective tools for identifying prominent research areas within a specific field. Our study utilized keyword network diagrams to analyze investigations pertaining to the association between obesity and asthma. The findings revealed several prominent research themes, including epidemiology, metabolic syndrome, pharmacological treatments, and inflammation. Recent research efforts have particularly focused on elucidating underlying mechanisms, exploring physiological mechanics, investigating comorbidities, and developing effective treatment strategies [62‒66]. The prevalence of these research directions signifies a multitude of promising avenues for further exploration in the field of obesity and asthma. By delving deeper into these areas, researchers can enhance their understanding of the complex relationship between obesity and asthma, ultimately leading to advancements in prevention and treatment approaches.

Our analysis of co-occurring keywords over the past 2 years has revealed emerging themes in investigations related to the link between obesity and asthma. Mendelian randomization, gut microbiome, inflammation response, gene, and biomarker research have emerged as prominent areas of study. Recent studies have shed light on the role of changes in gut bacteria in obesity-associated asthma and identified the pleiotropic nature of the ADRB2 gene as a potential candidate for association with both obesity and asthma [67, 68]. Moreover, abnormal levels of leptin and adiponectin have been observed in patients with obesity-associated asthma, indicating the presence of other unexplored factors that may influence the obesity-asthma relationship [69]. Overall, these studies have identified several research hotspots that are likely to direct future investigations in this field.

This study is subject to several limitations. First, it relied exclusively on data from the Web of Science core database, and only English-language articles and reviews were considered. This approach may introduce a potential selection bias. Nevertheless, the comprehensive number of retrieved papers was deemed adequate for providing a substantial overview of the current state of research [70]. Second, the challenges associated with accurately retrieving all relevant records stemmed from the diversity of keywords and authors sharing the same name. Despite these limitations, the study offers valuable insights into the relationship between obesity and asthma.

Our study employed the Web of Science Core Collection database and utilized VOSviewer software for a visual analysis of obesity and asthma literature spanning from 2013 to 2023. It moves beyond conventional research methods, offering a more intuitive visualization of the research content and thematic hotspots. Furthermore, the analytical results enable the prediction of potential future research directions in this domain. It examined the institutions engaged in research on these topics and identified significant research trends. The study also investigated the characteristics of the literature sources and the distribution of knowledge within the field. The findings from these analyses are summarized in the subsequent sections.

• 1.

  The research on the relationship between obesity and asthma has garnered increasing attention from the scientific community. The global publication output in this field exhibited an overall upward trend from 2013 to 2023, with fluctuations potentially reflecting the evolving research focus and the changing medical landscape during the study period.

• 2.

  The institutional analysis revealed that the USA, China, and Australia were the leading contributors to research on obesity and asthma. Notably, the USA demonstrated the most extensive international collaboration network in this field.

• 3.

  Examination of current research hotspots highlights two principal dimensions. First, the keyword co-occurrence analysis identified key research topics centered around obesity, asthma, BMI, children, and risk. Analysis of recent key terms has unveiled a promising research frontier. This includes the comorbidity of obesity and asthma, metabolism studies, mendelian randomization, gut microbiome, inflammation response, gene, and biomarker.

• 4.

  Based on the literature sources and knowledge distribution characteristics, the American Journal of Respiratory and Critical Care Medicine emerged as the predominant journal in this field, while Anne E. Dixon led with the highest publication count among authors.

• 5.

  The field of obesity and asthma research is currently undergoing a period of robust expansion, attracting widespread interest from scholars globally. China has emerged as a leading contributor in this domain. However, there remains scope to enhance collaboration among diverse institutions and research teams. To advance the field further, it is recommended that research organizations and groups strengthen their cooperative efforts, leverage integrated resources, and work toward standardizing the research approaches to provide more robust evidence and clarify the underlying mechanisms.

We express our gratitude to all participants for their valuable cooperation in this study.

Ethical statements are not applicable for this study given its exclusive reliance on previously published literature.

The authors declare that they have no conflicts of interest.

This research was funded by General Program of National Natural Science Foundation of China (NO.82370676) and Key Research and Development Program of Hunan province (NO. 2022SK2001).

The study was planned by P.C. and J.K.L. G.H.W., X.L.S., Z.L., L.Y.Z., and S.H.Z. were responsible for data acquisition and analysis. All authors have contributed significantly to the study and have given their approval for the final version of the manuscript.

The datasets used in this study have been deposited in online repositories for easy access and utilization. The specific names of the repository or repositories, along with the corresponding accession number(s), can be found within the article itself or in the online supplementary material section. By providing this information, we aim to promote transparency, reproducibility, and further exploration of the data by fellow researchers. Detailed instructions on accessing and utilizing the datasets are readily available for interested readers.