Tracking research trends and hotspots in sperm DNA fragmentation testing for the evaluation of male infertility: a scientometric analysis

Abstract

Background: This article describes the research trends in sperm DNA fragmentation (SDF) over the past 20 years (1999-2018) using a scientometric approach.

Methods: A stepwise approach was adopted to retrieve scientometric data (articles per year, authors, affiliations, journals, countries) from Scopus and analyze the publication pattern of SDF with reference to key areas of research in the field of Andrology.

Results: A total of 2121 articles were retrieved related to SDF. Our data revealed an increasing research trend in SDF (n = 33 to n = 173) over the past 20 years (R² = 0.894). Most productive country in publications was the USA (n = 450), while Agarwal A. (n = 129) being the most productive author. Most of the articles in SDF were primarily focused on lifestyle (n = 157), asthenozoospermia (n = 135) and varicocele (130). Mechanistic studies on SDF were published twice as much as prognostic/diagnostic studies, with significant emphasis on oxidative stress. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was the most widely used technique to evaluate SDF. Publications on SDF related to assisted reproductive techniques also showed a linear increasing trend (R² = 0.933).

Conclusions: Our analysis revealed an increasing trend in SDF publications predominantly investigating lifestyle, asthenozoospermia and varicocele conditions with TUNEL being the most widely used technique. A substantial increase in research is warranted to establish SDF as prognostic/diagnostic parameter to evaluate clinical scenarios and ART outcomes.

Keywords: DNA fragmentation; Diagnosis; Infertility, male; Prognosis; Publications; Scientometric analysis.

Fig. 1

Flow diagram depicting the stepwise analysis of publication trends in SDF. Subcategory “Astheno*/Oligoastheno*” includes articles on asthenozoospermia, asthenoteratozoospermia, oligoasthenozoospermia, and oligoasthenoteratozoospermia. UMI: unexplained male infertility, SCSA: sperm chromatin structure assay, SCD: sperm chromatin dispersion test, TUNEL: terminal deoxynucleotidyl transferase dUTP nick end labeling, ART: artificial reproductive techniques

Fig. 2

a Publication trends in SDF-based research over the past 20 years. b Analysis of the research trends based on types of publication. c Top 10 institutions based on the publications in SDF (1999–2018). d Contour/Heat map showing the publications in SDF (1999–2018). e International collaborations in SDF research. f Analysis of the research trends based on the origin of publications across the globe. g Contour/Heat map showing the top scientist working in the area of SDF. Heat map 2d and 2g shows gradient heat pattern (red, orange, yellow, green and blue) based on the number of publications from journal and author, respectively. The font size of the journal and author names are presented in an ascending manner with respect to an increasing number of publications. Only the names of journals and authors having higher number of publications are visible

Fig. 3

a Research trends on SDF-associated male infertility studies. b Top scientist investigating the role of SDF in male infertility

Fig. 4

a Publication trends on SDF based research on varicocele, oligozoospermia, Astheno*/Oligoastheno*, testicular cancer, unexplained male infertility (UMI), recurrent pregnancy loss (RPL). Astheno*/Oligoastheno* includes articles on asthenozoospermia, asthenoteratozoospermia, oligoasthenozoospermia, and oligoasthenoteratozoospermia. b Publication trends on SDF-based research on hypogonadism, obesity, lifestyle and occupational exposure

Fig. 5

Publication trends in mechanistic studies and prognostic/diagnostic studies on SDF

Fig. 6

Publication trend in SDF using TUNEL/SCSA/Comet/SCD between1999–2018

Fig. 7

a Publication trend in SDF-based ART studies between1999–2018. b Top scientist involved in SDF-based ART studies. c SDF-based ART studies: Collaboration network