An In-Depth Bibliometric Analysis and Current Perspective on Male infertility Research

Abstract

Purpose: Male infertility is emerging as a major, escalating global health problem that imposes the need to investigate research trends in male infertility. The purpose of this study is to analyze male infertility research trends in the past 20 years using the bibliometric database from Scopus.

Materials and methods: In order to perform an in-depth bibliometric analysis, we propose a 'Funnel Model', which includes several layers representing different sub-areas of male infertility research. Adopting this Funnel Model, using Scopus, we retrieved relevant bibliometric data (articles per year, authors, affiliations, journals, and countries) for various areas of male infertility research and performed descriptive statistics.

Results: The bibliometric analysis showed an exponential increase in male infertility research in the last 20 years. USA dominated in research output, with Agarwal, A. as the most prolific researcher. Testicular cancer, obesity and metabolic syndrome, and azoospermia were found to dominate male infertility research, whereas erectile dysfunction and unexplained male infertility had lesser attention. Interestingly, prognostic/diagnostic and mechanistic studies have significantly increased in parallel over the last 20 years. Furthermore, our bibliometric analysis revealed fewer publications in proteomics, transcriptomics and metabolomics when compared to genomics. Also, an increasing trend in publication was seen in assisted reproductive technology (ART) research.

Conclusions: An integrated and steep escalation in the field of omics and ART research appears to be a prerequisite for further development of future diagnostic and therapeutic strategies for male infertility.

Keywords: Bibliometric analysis; Diagnosis; Infertility, male; Prognosis; Publications.

Fig. 1. Schematic representation of the Funnel Model. Layer 1 represents overall trend in male infertility research; Layer 2 is a sub-classification of Layer 1 having a (azoospermia), b (erectile dysfunction, ED), c (hypogonadism), d (lifestyle), e (male genital tract infection), f (obesity and Metabolic Syndrome, MetS), g (occupational exposure), h (oligozoospermia), i (testicular cancer), j (unexplained male infertility, UMI), and k (varicocele); Layer 3 represents mechanistic and prognostic/diagnostic studies of male infertility; Layer 4 represents omics (genomics, transcriptomics, proteomics, and metabolomics)-based publications in male infertility; Layer 5 represents assisted reproductive technology (ART)-based publications on male infertility. Zone A is comprised of Layer 1 and 2. Publications in zone A defines the problem; Zone B is comprised of Layer 3 and Layer 4. Publications in zone B helps in understanding the basis of the problem. Zone C comprised of Layer 5 and publications in this zone provide possible solution(s) to the problem.

Fig. 2. Publication trend in male infertility research by year (A), country (B), affiliation (C), and author (D) over the past 20 years (1998–2017). CNRS: Centre National de la Recherche Scientifique, UCL: University College London.

Fig. 3. Publication trend in specific areas of male infertility research over the past 20 years. (A) Publication trend of varicocele, azoospermia, oligozoospermia, testicular cancer, erectile dysfunction, and male genital tract infection by year from 1998–2017. (B) Publication trends of unexplained male infertility (UMI), hypogonadism, obesity and metabolic syndrome, lifestyle, and occupational exposure by year from 1998–2017.

Fig. 4. Publication trends in mechanistic and prognostic/diagnostic studies over the past 20 years. (A) Trends in the number of articles on mechanistic studies of male infertility by year. (B) Top scientists in the research area of mechanistic studies of male infertility during the period 1998–2017. (C) Trends in the number of articles on prognostic or diagnostic studies of male infertility by year. (D) Top scientists involved in prognostic or diagnostic studies of male infertility during the period 1998–2017.

Fig. 5. (A) Publication trends in genomics, transcriptomics, proteomics, and metabolomics of male infertility by year from 1998–2017. Top scientists in the field of genomics (B), proteomics (C), transcriptomics (D), and metabolomics of male infertility (E) research during the period 1998–2017.

Fig. 6. (A) Publication trend in assisted reproductive technology (ART) by year from 1998–2017. (B) Top scientists in the field of ART related research during the period 1998–2017.