A Bibliometric Analysis of Childhood Obesity Research From China Indexed in Web of Science

Background: Childhood obesity (CHO) is a serious global health threat, whose prevalence in China has gradually increased in the past two decades. The study aimed to quantify and map the scientic output of research concerning CHO published from China though a Bibliometric perspective. Methods: CHO-related publications were retrieved from the Web of Science database by using the keywords ‘childhood obesity’, and ‘childhood overweight’. HistCite and Biblioshiny software were used to categorise and evaluate authors’, institutions’ and journals’ contribution. VOSviewer was used for network-visualisation. Results: A total of 230 CHO-related documents were identied from China (1900-2020), which was 3.8% of the global output of CHO research. The majority (74.8%) of the papers were research articles, and the average citations per document were 18.4. The results show a gradual increase in publication trend over the last 20 years. The leading institutions in CHO research were Peking University (n=22), Chinese CDC (19) and Chinese University of Hong Kong (18), while “Endocrinology Metabolism” (50) was the most decisive research eld. The most contributing authors included Wang YF (17), Xue H (11), and Ma GS (10), while “Obesity Reviews” (15) was the most-crucial journal. The most cited article was from Olds T et al. published in 2011. Conclusion: This analysis provides a historical perspective of progress in CHO research from China and has highlighted the leading role played by various stakeholders in addressing CHO. Besides, it highlights a need for more focus on CHO research as well as targeted interventions for effective prevention and control.


Introduction
Childhood obesity (CHO) has become a serious global health challenge, with an alarming increase in its prevalence all over the world [1]. The condition affects both developed and developing countries. According to the World Health Organisation, over 41 million children under the age of ve were estimated to be overweight or obese worldwide in 2016. Besides, approximately half of these obese children lived in Asia, whereas one quarter lived in Africa [2]. In the last decades, the prevalence of CHO in China has gradually increased, now almost equal to that in developed countries [1,3]. Between 2000 and 2011, the prevalence of CHO in China nearly tripled from 6.5-16.8% [4].
The notable causes of CHO include unhealthy eating habits, lack of physical activities, family history, among others [5,6,7]. If unchecked, CHO predisposes children to several chronic health conditions such as diabetes, high cholesterol, hypertension, heart disease, diabetes, asthma, joint pain, among others [8,9].
Besides, CHO affects children's self-esteem due to poor self-image and depression [10]. Without intervention, obese children will likely continue to be overweight during adolescence and adulthood, which is linked to a high risk of life-limiting comorbidities [6].
Research shows that approximately 260 million people in China are overweight or obese, and 50% of them are reported in the major cities in China [11,12]. In a recent study conducted by Musa et al., a signi cant change in overweight and obesity rate among children and adolescents in Jiangsu Province, China was reported. However, the rate remains higher among males compared with females, and overweight and obesity rate was highest in urban children compared with rural where substantial change has been reported in early childhood, middle childhood and adolescence [12]. Although China has undergone rapid socioeconomic and infrastructure development, several serious problems impeding child growth and development were still reported [13,14].
In response to the increasing burden of CHO in China, several studies have been done to address this public health challenge. This raises the need to collectively quantify and evaluate CHO research, and give a historical perspective, owing to the considerable efforts and resources that have been injected into the control, treatment and prevention of CHO.
This study thus aimed to map research efforts related to the CHO published from China through a bibliometric perspective using documents indexed in the Web of Science database. The study would help ll vital gaps and provide bene cial insight and information to public health authorities and researchers into the control, treatment and prevention of childhood obesity.

Study design.
This study used a Bibliometric analysis, a technic that has been progressively used as a tool and basis for monitoring research performance of various scienti c disciplines, as well as supporting appropriate policy actions [15][16][17].
Data source.
The study used the Web of Science Core Collection (WoS), which is a multi-disciplinary scienti c citation indexing database and maintained by Thomson Reuters (New York, NY, USA) [18]. The database covers the most important international journals. Ethical approval for this study was not necessary because the data used were obtained from a public database and involved no interaction with human or animal subjects.
Search strategy.
The study used keywords: "Childhood obesity" or "Childhood overweight" to retrieve relevant documents from WoS published within 1900-2020 (14 th March). To maximise the accuracy of the retrieved research output, the keyword was searched in the article titles and was limited to only articles from China, Hong Bibliometric Analysis.
The identi ed relevant documents were downloaded as a plain text format for further analysis. The study mainly reported descriptive statistics. The research trends and selected bibliometric indicators were classi ed and analysed using HistCite and "Bibliometrix app."-(using R-studio cloud) [19]. These included the distribution and frequency of document types, keywords, most productive territories, institutions, authors, research eld and journals, as well as h-index, impact factor and total citations. In this regard, the Journal impact factors were obtained from the Journal Citation Reports (JCR) © Ranking: 2018 [20]. In addition, Microsoft excel and VosViewer (Van Eck & Waltman, Leiden University, The Netherlands) were used for data mining, mapping and visualisation of the network analyses [21].

Document types and trends of publication
The initial search identi ed a total of 6,049 documents from all countries and after re ning the search to China and Taiwan, they reduced to 230 (3.8%). For comparison, USA had 2,513 (41.5%) CHO documents, followed by UK 615 (15%) and Australia 373 (6.2%).
The 230 documents were considered for analysis, of which only one article was in the Chinese language, and the rest in the English language. Of the total papers, 16 were Single-authored documents, while 172 (74.8%) were research articles, 23 (10%) reviews, and 21 (9.1%) meeting abstracts, 8 (3.5%) editorial material and the rest were of other document types (Fig. 1).
Globally, CHO research begun in 1996 from which it had gradually increased over the last two decades.  Table 1).
The analysed articles belonged to 48 research elds categorised according to the WoS elds, and of these, ten elds had atleast 7 articles. The most crucial research eld included "Endocrinology Metabolism" (50), "Public Environmental Occupational Health" (46), "Pediatrics" (44), and "Nutrition Dietetics" (33) among others, as shown in table 1.  Most productive Journals.
The retrieved CHO articles were published in 121 journals, of which 10 of them published 5 or more papers. It was noted that foreign journals dominated the list, especially UK journals. The most ten productive journals included; "Obesity Reviews" (15), "Biomedical and Environmental Sciences" (11), "BMC Public Health" (8), among others. The impact factor of the 10 top productive journals ranged from 1.17 to 7.34 (Table 3). Collaborations and Network analysis The analysis showed that China collaborated with 28 countries within CHO research. The strongest partnership was with the USA, with which it produced 90 studies, followed by Australia (20), UK (28) Table 4). The 10 top-cited papers altogether were cited 1,595 times in the last 20 years.  (83), adolescents (53), amongst others, as visualised in g. 5 (a) and (b). The size and centrality of the word re ect its frequency and magnitude.
Note that keywords plus are words that frequently appear in the titles of an article's references, but do not appear in the title of the article itself, and are vital in exploring the knowledge structure of scienti c elds.

Discussion
This bibliometric analysis provided an insight in the trend and scienti c output of CHO-related publications from China. The study revealed that the documents were produced within the last 20 years, with over 80% being published in the recent ten years. This can be explained by the rapid increase in the prevalence of CHO in china, which has almost tripled just within the last two decades [4]. This has resulted in increased attention being given to addressing CHO, which is re ected in research output. However, when compared to the global production, CHO research from china is less (3.8%), implying more focus is still required in this eld.
Of the analysed documents, over 74.8% were original research articles, followed by reviews among other documents. The published original articles directly translate into the efforts towards CHO research during the last two decades.
The analysis noted that the list of most productive journals was dominated by the USA and other foreign journals, in which English is the dominant language used. This can be because most of the Chinese journals are not indexed in international databases. This implies that the preventive recommendations of CHO made by these studies may not be fully accessed to the Chinese community, especially if not translated into Chinese. Therefore there is a need to build and strengthen local journals and databases to improve on the regional as well as international recognition of CHO studies from China.
Research concerning CHO was mainly funded by Chinese public or government institutions of which National Natural Science Foundation of China nanced led the list. However, several USA institutions had a signi cant role in nancing CHO studies in China, which included National Institutes of Health NIH USA, among others. This has also been noted in other previous studies [15,22]. Besides, Coca-Cola was the only food processing/beverage company noted to nance CHO research in China. It should be noted that the food processing industry plays a signi cant role in public nutrition and health, which is a vital predisposing factor to CHO and other health issues [23,24,25]. Addressing CHO should be a joint responsibility; thus, the food processing industry and the private sector, in general, should increase its involvement in CHO research.
Network analysis showed that China exhibited a considerable degree of collaboration with several countries in carrying out CHO research. The most robust research collaboration was with the USA, followed by other countries. This further demonstrates the importance of knowledge transfer and sharing in addressing public health issues [26].
The analysis showed that the leading institutions of CHO research are mainly Chinese Universities, where Peking University lead the list, followed by Chinese CDC, among others. Besides, the most contributing authors of CHO research included both Chinese and authors of other nationalities. The most productive authors included Wang YF, Xue H, and Ma GS. Furthermore, network analysis revealed authors with the highest collaborations. This information could be helpful to future researchers in this eld, to quickly identify the crucial researchers for potential partnerships or even consultation, concerning CHO research.
The most highly cited article was a review written by Olds T et al. in 2011, which summarised the evidence of the stagnant high prevalence of CHO using data from nine countries including China [27]. The top citations could be because this article had a broader coverage; addressing CHO in several countries. As noted by previous studies, CHO obesity is still not considered a serious public health issue by some communities in China; which could be due to the cultural perception of chubby children as healthy and a display of family's wealth [4,11]. This calls for culturally-sensitive health promotion programs to curb the incidence and prevalence of CHO in China [28]. In addition, implementing and strengthening of policies on the marketing of foods to children are needed [29,30], if the World Health Organization's target of "no increase in obesity prevalence by 2025" is to be achieved [2,31].
The most key research elds in CHO were "Endocrinology Metabolism" "Public Environmental Occupational Health", "Pediatrics", "Nutrition Dietetics", amongst others. These elds are a deeper re ection of the pathogenesis and aetiology of CHO [32,33]. Besides, the analysis of keywords disclosed that the studies covered various crucial aspects of CHO, including prevalence, causes and risk factors, social-economic effects as well as prevention and treatment. Body mass index (BMI) is also highlighted as the keyword with the most co-occurrence among the analysed articles. This is because BMI is the central index for the classi cation of overweight and obesity, and so it cuts across most studies concerning CHO [34,35].
Like any other bibliometric studies, this one also had some limitations, such as the use of a single database, not all Chinese journals are indexed in the WoS, thus a possibility of missing out some key publications [16,17]. Besides, the citation numbers might be deceptive [22], owing to self-citations, time of publications, among other factors. Therefore, further studies are required using different databases to validate these ndings.

Conclusions
The study tried to summary CHO research output from China, in which it highlighted a gradual increase in the last two decades. The study has revealed the leading roles played by various authors, institutions and journals in addressing CHO. The study also identi ed signi cant collaboration exhibited by China and other countries in CHO research, which vital as it enables knowledge sharing and transfer. However, the study has noted an implementation gap of the research recommendations evidenced by the increasing prevalence of CHO in China, especially in the last ten years. Therefore more efforts are needed in terms of focus and funding of CHO research, as well as strengthening local journals and indexing databases.
Data Availability