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Introduction
Precocious puberty (PP) is a pathology defined by the appearance of visible or secondary sexual characteristics before the average age, occurring before 8 years for females and before 9 years for males [1]. The epidemiology of PP can vary by sex, with incidences of 1 case per 10,000 boys and 8 cases per 10,000 girls [1, 2]. Additionally, the onset of sexual characteristics may vary by race, as indicated by a cohort study in which the appearance of sexual characteristics at age 7 years was higher in African American girls (48.3%) compared to white girls (14.7%) [3].
Precocious puberty has long-term effects that are particularly important for girls, the most relevant and frequent being shorter adult height, early bone maturation leading to early osteoporosis, early and short menarche periods, and infertility, which could lead to the development of breast carcinomas, increased risk of obesity and diabetes, as well as mental health effects such as depression and anxiety, which, in turn, may lead to eating disorders and decreased self-esteem [4–6].
Overall, treatment focuses on controlling the early activation of sexual/reproductive organs. Treatment with GnRH analogues yields good results in delaying sexual development and even in achieving adequate adult height [7], while simultaneously contributing to psychosocial development to improve the mental health of patients, particularly during childhood, puberty, and adolescence [8].
While it has been considered that the majority (between 80 to 90%) of cases are idiopathic, precocious puberty remains a pathology with a poorly understood origin. However, in the last decade, efforts to understand this origin have been focused on the genetic aspect [9, 10]. It is also important to recognise that, due to its low incidence, some important aspects such as adverse treatment outcomes or long-term follow-up may be less feasible, and while long-term results are defined, they still generate many questions [11, 12].
Although there is information about diagnosis and treatment, research on the origin and especially long-term outcomes plays an important role in the development of new treatments. It is also important to know where the information is heading in order to stay at the forefront with new knowledge about PP. A documentary approach could explain and allow physicians and healthcare personnel to understand the global research situation of PP, as well as to identify which topics are gaining relevance, particularly after being affected by a global pandemic [13].
A bibliometric and cienciometric analysis would allow us to have a better grasp of new research trends, as well as to identify the indexed documents and journals that are most likely to publish about PP. Therefore, this study aims to understand the research situation through a cienciometric analysis of documents published in the Web of Science database on PP.
Material and methods
Design and unit of analysis
A retrospective study with a cienciometric approach was conducted. The unit of analysis consisted of documents published on “precocious puberty” during the period 2000 to 2023 in the Web of Science (WoS) database.
Inclusion and exclusion criteria
Included were studies specifically addressing the topic of “precocious puberty” as a central theme, whether as research or review articles. Thus, only original articles and review articles (umbrella, narrative, systematic, or scoping) were included, along with consensus statements and clinical practice guidelines published in peer-reviewed journals. Only studies published during the period 2000 to 2023 were included, preprints, editorials, and conference abstracts were excluded, and only studies finally published in journals indexed in WoS were considered (Fig. 1).
Source and search strategy
Data extraction was performed based on a systematic search specifically on the thematic axis of “precocious puberty”. Terms were analysed based on MeSH (Medical Subject Heading) search in PubMed and Emtree terms in Embase to identify key terms (Supplementary Material). The Web of Science database was chosen for being considered one of the strictest databases for journal inclusion and indexing worldwide. The complete search strategy is available in the supplementary material, and the search was conducted on 16 February 2024.
Data collection and cienciometric analysis
Following the identification and selection of documents based on the inclusion and exclusion criteria, data were exported in BibTeX format for further analysis. Cienciometric data were collected based on the number of documents (the number of documents per year was evaluated using a coefficient of determination by the Spearman test), number of citations per document, most prolific author and country, collaboration networks, and co-occurrence of keywords. Journal or document aspects such as journal quartile and type of document or open access were inspected manually, with the quartile identified using the Clarivate “Journal Citation Reports” platform. For the analysis, RStudio was used with the “bibliometrix” library and the “biblioshiny” web application [14]. Results are presented using frequencies and percentages in descriptive tables and images (collaboration networks and co-occurrence) for better visualisation.
Ethical considerations
This study is based on the analysis of publicly accessible data using the previously provided formula. No personally identifiable information not already published and openly accessible is displayed. Additionally, the data collected for this study are freely available for analysis and are in the supplementary material (Supplementary Material). Due to its nature as secondary analysis, having published documents as the unit of analysis, and not using information that could be harmful, this study does not require approval from an institutional ethics committee.
Results
A total of 3,556 documents were analysed, with annual scientific production showing steady growth, obtaining a coefficient of determination of 0.79. Scientific production in the year 2000 was 105, while in 2023 it was 274, indicating annual growth as shown in Figure 2. Similarly, the number of authors globally and by country increased significantly, particularly in the United States (108 authors in 2000 and 2,998 authors in 2023), China (0 authors in 2000 and 1,958 authors in 2023), and Italy (97 authors in 2000 and 1,230 in 2023). Detailed annual growth of authors by country can be observed in the supplementary material.
Figure 2
Annual scientific production on precocious puberty in Web of Science during 2000–2023. A coefficient of determination of 0.7871 is observed (p < 0.001)
In terms of the absolute number of documents, the United States has the highest number of documents with 837, followed by the People’s Republic of China with 391 and Italy with 318. It is worth mentioning that these documents may have international collaboration. In this regard, there are over 30 documents in collaboration between the United States and Brazil, as well as between the United States and Italy; over 20 documents in collaboration between the United States and the United Kingdom, and also between the United States and the People’s Republic of China (Fig. 3).
Figure 3
Number of documents per country on precocious puberty in Web of Science and collaboration map during 2000–2023
The most prolific author is Collins MT with 55 articles addressing the topic of “precocious puberty”, followed by Latrónico AC with 50 and Boyce AM with 44 (Supplementary Material). On the other hand, the author collaboration network indicates well-defined clusters of collaboration, with the largest being the collaboration group between Latronico AC, Brito VN, and Mendonca BB; and Collins MT, Boyce AM, and Robey PG. The collaboration network among authors from the People’s Republic of China is well-defined, although they do not have as many collaborative documents among themselves as the groups mentioned previously (Fig. 4).
Figure 4
Collaboration network among authors with documents on precocious puberty in Web of Science during 2000–2023. Each colour represents a cluster or research group with at least one co-authored document, and the thickness of connecting lines represents the number of documents on which they collaborated
In terms of the most relevant journals and documents, it was found that the “Journal of Pediatric Endocrinology & Metabolism” had the highest number of documents during the study period (n = 306). This journal has an impact factor of 1.4 for 2022 and is classified in the fields of paediatrics and endocrinology and metabolism, both being in Q4. On the other hand, the next journal with the highest number of documents is the “Journal of Clinical Endocrinology & Metabolism” (n = 144). However, compared to the first journal, this one maintains an impact factor of 5.8 for 2022 and is only classified in the field of endocrinology, staying in the first quartile (Q1) (Table I). Regarding the most relevant documents, the journal with the highest number of citations is The Timing of Normal Puberty and the Age Limits of Sexual Precocity: Variations around the World, Secular Trends, and Changes after Migration, published in 2003 in the journal “Endocrine Reviews” (Q1), with Anne-Simone Parent as the first author. It had 1038 citations at the time of the search. This is a narrative review and is fully open access. The second most cited article is Mutations of the gene encoding the protein kinase A type I-alpha regulatory subunit in patients with the Carney complex, published in 2000 in the journal Nature Genetics (Q1), with LS Kirschner as the first author, which has 787 citations at the time of the search. In contrast to the previous document, this one presents original results but is not fully open access (Table II).
Table I
The most relevant journals on precocious puberty in WOS during 2000-2023
Table II
Ten most cited documents on precocious puberty in WOS during 2000-2023
Regarding the most used keywords per author, there is a centrality towards “precocious puberty”, which directly connects with all the remaining keywords. There are two well-defined clusters, with “McCune-Albright syndrome” being another separate topic. The words showing a connection line have at least 5 uses among themselves (Supplementary Material). On the other hand, emerging topics show an increasing use of the word “COVID-19” since 2022, as well as “dlk1” and “mkrn3” since 2020 and 2019, respectively, outside of “precocious puberty”. “Central precocious puberty” and “McCune Albright” were also the most used words per year with at least 10 uses during that year (Supplementary Material).
Discussion
This study analysed scientific production based on original articles, review documents, consensus statements, and clinical practice guidelines published in article format. The results indicate that scientific production increased mainly in the United States and China, where the highest number of documents and authors per document were obtained. As in various topics, scientific production in the United States grows potentially and rapidly, not only in health sciences but also steadily in all areas [15]. Similarly, but at a faster pace, production in the People’s Republic of China has grown strongly, particularly in the last decade [16], surpassing even the contributions that other industrialised countries such as the United Kingdom or Brazil can provide. This strengthens the contributions that can be made regarding PP; research in developed countries (including collaboration between such countries) allows high-end laboratories and technologies [16] to explore molecular aspects of the disease, thus better understanding its origin and potentially directing PP treatments based on these new findings.
Regarding the most prolific author and the most important document, it is important to mention that despite Collins MT and Latronico AC being prolific authors, they are not the first authors of the most cited articles. Another important aspect is that the most cited article is a narrative review, a situation that could be due to narrative reviews largely synthesising the information found individually [17]. However, faced with this dilemma, the correct option would be to cite the original source that the narrative review also cited at that time [18].
One of the most relevant aspects is international collaboration in scientific research. By observing the collaboration network, 3 main clusters composed of authors affiliated with institutions from the same country, specifically from the United States, Brazil, and China, are identified. However, it is important to encourage collaboration among authors from different countries due to the epidemiological variability of PP according to geographical area, with African countries having a high incidence of PP but less scientific collaboration [19]. Additionally, international collaboration will allow the exchange of ideas, leveraging the different cultural and social perspectives of each author, thereby improving both the quantity and quality of research studies [20].
It is also necessary to mention that the journal “Journal of Pediatric Endocrinology & Metabolism”, which has been in the lower quartile since its inclusion in Web of Science, is intriguing. Despite having more than double the number of documents on PP compared to its successor, the “Journal of Clinical Endocrinology & Metabolism”, it has not managed to increase its quartile ranking. It is important to note that the results suggest that inclusion in 2 categories does not lead to a better quartile, as is the case with “Hormone Research in Paediatrics” and “Journal of Clinical Research in Pediatric Endocrinology”, both specialising in paediatrics and endocrinology/metabolism, similarly to the first journal mentioned in this paragraph. However, these statements are speculative and based only on the results obtained; a more in-depth analysis of each specialised journal is needed to draw more evidence-based conclusions.
Another important aspect is the most developed research topics. We found that the keywords “precocious puberty” and “McCune-Albright syndrome” were the most used, with the latter being a hereditary disease that includes PP as one of its signs [21]. Likewise, in recent years, topics related to COVID-19 emerged due to the pandemic’s influence on generating evidence on various issues [22]. Similarly, topics related to genes “dlk1” and “mkrn3” emerged, indicating the increase in research studies in the genetic field.
Limitations
It is necessary to acknowledge some limitations in the present study. First, the systematic search was conducted only in WOS, which could underestimate the actual number of publications on PP; however, this database covers a vast amount of scientific information, and inclusion in the core collection is considered more rigorous [23]. Another limitation is that detailed cienciometric results were not presented due to the large number of documents collected. However, a specific analysis of original studies could reveal the types of studies being conducted most frequently (experimental, clinical trials, observational, etc.), as well as the type of funding received, or whether the documents are published in fully open access. It is expected that future studies may include more precise bibliometric indicators to identify experimental studies, observational studies, or case reports, and define specific areas such as medical sciences, genetics, or social sciences. Despite these limitations, these findings provide information for decision-making when proposing research ideas based on the existing scientific literature gap.
Conclusions
A steady increase in scientific production on PP worldwide was observed, with the United States and China being the countries with the most published scientific documents. International collaboration mainly occurred between the United States and countries in Latin America, Europe, and Asia. However, most collaboration networks occurred among authors from the same country. The highest number of documents was found in the “Journal of Pediatric Endocrinology & Metabolism”, a lower impact journal (Q4). Regarding emerging topics, these mainly cover genetic aspects. It is necessary for future studies to include more precise bibliometric indicators such as study design and funding, among others.
