Effect of Selenium on Thyroid Disorders: Scientometric Analysis

Abstract

Background: Association of Selenium (Se) deficiency, an essential trace element, has been found with human diseases. Identifying literature trends on the effects of Se on the thyroid may guide in planning future studies.

Methods: A literature search was conducted using the Web of Science database to identify studies on Se and the thyroid published over the 20 years duration (1995-Dec 2014). Scientometric indices were used to draw field maps. The scientific processes, structure, evidence history, and international collaborations were included in the map. The most influential authors, journals, institutions, and countries were also examined.

Results: Our search identified 184 research and review papers. The number of scientific studies on Se and the thyroid has been irregular, but interest in this topic has increased in recent years. The highest number of studies was published in 2014 (16 papers) and overall growth factor of publication was 3.78. Overall, 744 authors from 282 institutions in 43 countries published in this field. The author J. Kohrle (828 citations, 14 publications), and German scientists (1272 citations, 30 publications) were most influential.

Conclusion: This study reveals the interrelationships between different publications on the effects of Se on the thyroid. Leading scientific issues and their extent of impact were successfully determined by examining citations. The results of systematic citations and mapping fields can be used to assist in policy and management contexts.

Keywords: Field maps; International collaborations; Scientometric analysis; Selenium; Thyroid disorders.

Fig. 1:

Number of articles identified with the search term, “selenium effect on thyroid disorders.” The black line represents the model that best fit the data (y = 5.6494e^0.0378x, R² = 0.2356)

Fig. 2:

Number of citations that using the search term, “selenium effect on thyroid disorders”

Fig. 3:

Historiogram map of research identified using the search term, “selenium effect on thyroid disorders”. Numbers in the historiogram represent the number of articles shared by these 184 papers

Fig. 4:

Distribution of interrelation of subject categories for papers on “selenium effect on thyroid disorders.” Dot size is proportional to the betweenness centrality. Lines between subjects indicate a relationship between those subjects and the thickness of the line indicate the strength of the link. The color of the line indicates the year in which the two related subjects frequently appeared in the same articles (see color key at top of figure)

Fig. 5:

Subject clustering of articles on “selenium effect on thyroid disorders.” The subject clustering map was created with CiteSpace software. Squares represent terms in the articles, lines represent relationships between mentioned terms, and colors indicate relationship clusters (21 clusters in all) created according to the relationship and nearest of terms

Fig. 6:

Subject distribution and clustering of them in the field of “selenium effect on thyroid disorders”

Fig. 7:

International collaborations that produced publications on the “selenium effect on thyroid disorders”. Lines represent collaborations between countries and the data point size is proportional to the number of publications produced in each country