Top 100 Most Cited Studies in Obesity Research: A Bibliometric Analysis

*Tauseef Ahmad*

### **Abstract**

Obesity represents a major global public health problem. In the past few decades the prevalence of obesity has increased worldwide. In 2016, an estimated 1.9 billion adults were overweight; of these more than 650 million were obese. There is an urgent need for potential solutions and deeper understanding of the risk factors responsible for obesity. A bibliometric analysis study was designed to provide a comprehensive overview of top 100 most cited studies on obesity indexed in Web of Science database. The online search was conducted on June 6, 2021 using the keywords "Obesity" OR "Obese" OR "Overweight" in title filed with no limitations on document types or languages. The top 100 cited studies were selected in descending order based on number of citations. The obtained data were imported in to Microsoft Excel 2019 to extract the basic information such as title, authors name, journal name, year of publication and total citations. In addition, the data were also imported in to HistCite™ for further citation analysis, and VOSviewer software for windows to plot the data for network visualization mapping. The initial search retrieved a total of 167,553 documents on obesity. Of the total retrieved documents, only top 100 most cited studies on obesity were included for further analysis. These studies were published from 1982 to 2017 in English language. Most of the studies were published as an article (n = 84). The highly cited study on obesity was "Establishing a standard definition for child overweight and obesity worldwide: international survey" published in BMJ-British Medical Journal (Impact Factor 39.890, Incites Journal Citation Reports, 2021) in 2000 cited 10,543 times. The average number of citations per study was 2,947.22 (ranging from 1,566 to 10,543 citations). Two studies had more than 10,000 citations. A total of 2,272 authors from 111 countries were involved. The most prolific author was Flegal KM authored 14 studies with 53,558 citations. The highly active country in obesity research was United States of America. The included studies were published in 33 journals. The most attractive journal was JAMA-Journal of the American Medical Association (Impact Factor 56.272) published 17 studies and cited globally 51,853 times. The most frequently used keywords were obesity (n = 87) and overweight (n = 22). The countries with highest total link strength was United States of America (n = 155), followed by England (n = 140), and Scotland (n = 130). Our results show that most number of highly cited studies were published in developed countries. The findings of this study can serve as a standard benchmark for researchers to provide the quality bibliographic references and insights into the future research trends and scientific cooperation in obesity research.

**Keywords:** Obesity, Overweight, bibliometric analysis

### **1. Introduction**

Obesity represents a major public health challenge, in the past few decades the prevalence of obesity has increased worldwide and associated with serious adverse health outcomes [1, 2]. According to the statistics of World Health Organization, in 2016, an estimated 1.9 billion adults (18 years and older) were overweight, of these more than 650 million were obese. In 2019, 38 million children (under age of 5 years) were overweight or obese [3].

Obesity associated comorbidities including certain cancer, depression, fatty liver disease, hepatic steatosis, hyperlipidemia, hypertension, obstructive sleep apnea, orthopedic conditions, type 2 diabetes mellitus and social isolation [1, 4, 5]. There is an urgent need for potential solutions and deeper understanding of the risk factors responsible for obesity.

Bibliometric type studies are of great interest, conducted not only to present an overall overview of the published scientific literature but also critical and subjective summarization of the most influential scientific studies [6–8].

#### **2. Aim**

This study aimed to provide a comprehensive overview of top 100 most cited studies on obesity. The finding can serve as a standard benchmark for researchers and to provide the quality bibliographic references.

#### **3. Methods**

#### **3.1 Study design**

Bibliometric citation analysis study.

#### **3.2 Searching strategy and database**

On June 6, 2021 the online search was conducted on Web of Science, Core Collection database (Philadelphia, Pennsylvania, United State of America). The search keywords used were "Obesity" OR "Obese" OR "Overweight" in title filed with no limitations on documents types or languages. The top 100 cited studies were selected in descending order based on number of citations.

#### **3.3 Data extraction**

The obtained studies were imported in to Microsoft Excel 2019 to extract the basic information such as title, authors name, journal name, year of publication and total citations. In addition, the downloaded dataset were imported in to HistCite™ for further citation analysis.

#### **3.4 Visualization network**

Visualization network co-authorship countries and co-occurrence all keywords were plotted by using VOSviewer software version 1.6.15 (https://www.vosviewer. com/) for windows.

*Top 100 Most Cited Studies in Obesity Research: A Bibliometric Analysis DOI: http://dx.doi.org/10.5772/intechopen.98877*

## **4. Ethical approval**

This study did not involve any human or animal subjects, thus, ethical approval was not required.

#### **5. Results**

The initial search retrieved a total of 167,553 documents on obesity indexed in Web of Science database. Of the total retrieved documents, only top 100 most studies on obesity were included in this study. The included studies were published in English language. Most of the studies were published as an article (n = 84) followed by review (n = 14) and letter (n = 1). The average number of citations per study was 2,947.22, ranging from 1,566 to 10,543 citations.

The most cited study on obesity was "Establishing a standard definition for child overweight and obesity worldwide: international survey" published in BMJ-British Medical Journal in 2000 cited 10,543 times. Another study "Positional cloning of the mouse obese gene and its human homolog" published in Nature in 1994 was cited 10,214 times. A total of 10 studies were cited more than 5,000 times. Furthermore, 52 studies were cited at least 2,000 times, while the remaining studies were cited more than 1,500 times. The top 100 studies on obesity is presented in **Table 1**.

#### **5.1 Most prolific authors**

A total of 2,272 authors contributed to top 100 most cited studies. The most prolific author was Flegal KM authored 14 studies with 53,558 citations, followed by followed by Carroll MD (n = 10, citations = 36,950), and Ogden CL (n = 9, citations = 34,784). Only nine authors authored at least five studies as shown in **Table 2**. In addition, only 22 authors contributed in at least three studies.

#### **5.2 Most active countries**

A total 111 countries were involved in top 100 most cited studies on obesity. The most active country was United States of America (studies contributed: 75, citations: 217,788), followed by United Kingdom (studies contributed: 18, citations: 57,015), Canada (studies contributed: 9, citations: 17,920), Japan (studies contributed: 9, citations: 26,695), France (studies contributed: 8, citations: 21,228), Sweden (studies contributed: 8, citations: 20,632), and Netherlands (studies contributed: 7, citations: 13,018) as shown in **Table 3**. Only 21 countries were involved at least in four studies.

#### **5.3 Journals**

The top 100 most cited studies were published in 33 journals. The most attractive journal was JAMA-Journal of the American Medical Association published 17 studies and cited globally 51,853 times as shown in **Table 4**. Only seven journals published at least 4 studies, six journals published two studies each, while the remaining journals published a single study each.

#### **5.4 Commonly used keywords**

A total of 366 keywords were used in the top 100 most cited studies. The most widely used keywords were obesity (n = 87) and overweight (n = 22) as shown in **Table 5**.



*Top 100 Most Cited Studies in Obesity Research: A Bibliometric Analysis DOI: http://dx.doi.org/10.5772/intechopen.98877*


*Note: LCS: Local citation score; LCS/t: Local citation score per year; GCS: Global citation score; GCS/t: Global citation score per year.*

#### **Table 1.**

*Top 100 most cited studies on obesity.*


*Note: LCS: Local citation score; LCS/t: Local citation score per year; GCS: Global citation score; GCS/t: Global citation score per year.*

#### **Table 2.** *Authors with at least 4 studies.*


#### *Top 100 Most Cited Studies in Obesity Research: A Bibliometric Analysis DOI: http://dx.doi.org/10.5772/intechopen.98877*

#### **Table 3.**

*Country with at least 3 studies.*


*Note: IF: Impact Factor, Incites Journal Citation Reports, 2021; Q: Quartile; LCS: Local citation score; LCS/t: Local citation score per year; GCS: Global citation score; GCS/t: Global citation score per year.*

#### **Table 4.**

*Journals published at least 4 studies.*

#### **5.5 Year of publication**

The top 100 most cited on obesity were published from 1982 to 2017 as shown in **Figure 1**. The highest number of studies were published in 2006 (n = 9, citations = 29,552) and 2007 (n = 7, citations = 19,035) as presented in **Figures 1** and **2**.

#### *Role of Obesity in Human Health and Disease*


*Note: LCS: Local citation score; GCS: Global citation score.*

#### **Table 5.**

*The keywords used at least ten times.*

**Figure 1.** *Publication years of top 100 most cited studies in obesity research.*

#### **5.6 Co-authorship countries network visualization**

The minimum number of studies for a country was fixed at 3. Of the total countries, only 38 countries were plotted based on total link strength (TLS) as shown in **Figure 3**. The countries with highest TLS were United States of America (155), England (140), and Scotland (130).

#### **5.7 Co-occurrence all keywords network visualization**

Of the total keywords, only 69 were plotted as shown in **Figure 4**. The keyword body-mass index has the highest TLS 117, followed by overweight (65), adiposetissue (56), prevalence (53), weight (52), and obesity (49).

*Top 100 Most Cited Studies in Obesity Research: A Bibliometric Analysis DOI: http://dx.doi.org/10.5772/intechopen.98877*

**Figure 2.** *Total global citation score per year of top 100 most cited studies in obesity research.*

**Figure 3.**

*Co-authorship countries network visualization. Two clusters are formed; red color represents cluster 1 (24 items), and green color represents cluster 2 (14 items).*

#### **6. Discussion**

In recent years, bibliometric type studies have been increased significantly, these studies not only recognize the most influential studies in certain area but also determine the research shift and other important insights into the bibliometric parameters.

#### **Figure 4.**

*Co-occurrence all keywords network visualization. Three clusters are formed; red color represents cluster 1 (29 items), green color represents cluster 2 (26 items), and blue color represents cluster 3 (14 items).*

Globally, obesity is a major public health problem and the prevalence has increased in the past few decades. Therefore, this study was undertaken to recognize the most influential studies in obesity research and provide essential bibliographic information. To the best of our knowledge this is the first bibliometric analysis on top 100 most cited studies on obesity indexed in Web of Science database. The highly cited study in obesity research received a total of 10,543 citations. The study published in a highly rated journal in medicine had an impact factor of 39.890 and placed in quartile 1 (Q1) category. The study entitled "Establishing a standard definition for child overweight and obesity worldwide: international survey" provides cut off points for body mass index in childhood of six large nationally representative cross sectional growth studies [9].

Another study received a total of 10,218 citations. The study titled "Positional cloning of the mouse obese gene and its human homologue" discusses the potential role of obese gene and these genes may function as part of a signaling pathway from adipose tissue that acts to regulate the size of the body fat depot [10].

The top 100 most cited were published in 33 journals. The most attractive and core journals in obesity research were JAMA-Journal of the American Medical Association (n = 17), and Nature (n = 14) had an impact factor of 56.272, and 49.962 respectively. A total of 31 studies were published in these two journals with a total citations of 100,377, thus representing the quality of work and aiming of the authors for high impact factor journals. Influential studies on obesity were published in higher impact factor journals. Furthermore, studies published in higher impact factor journals are more likely to be cited by the scientific community. The impact factor shows importance and quality of a journal [109]. The top three authors based on number of studies in obesity research were Flegal KM (n = 14, citations = 53,558), followed by Carroll MD (n = 10, citations = 36,950), and Ogden CL (n = 9, citations = 34,784). In our study, the leading country was United States of America contributed in a total of 75 studies with a total citations of 217,788. The finding is in line with studies in other research areas [110–113].

#### **7. Conclusion**

This study provides a comprehensive information of the most cited studies in obesity research. Majority of the most cited studies were published by

*Top 100 Most Cited Studies in Obesity Research: A Bibliometric Analysis DOI: http://dx.doi.org/10.5772/intechopen.98877*

developed countries in higher impact factor journals. The current study might be helpful to researchers for insights into the future research trends and scientific cooperation.
