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The uterine fibroid/myoma tumour: analysis of the global research architecture using density-equalizing mapping

  • Dörthe Brüggmann
    Correspondence
    Corresponding author.
    Affiliations
    Department of Gynecology and Obstetrics, Goethe-University, Frankfurt, Germany

    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany

    Department of Obstetrics and Gynecology, Keck School of Medicine of USC, Los Angeles, California, USA
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  • Frank Louwen
    Affiliations
    Department of Gynecology and Obstetrics, Goethe-University, Frankfurt, Germany
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  • Tatjana Braun
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Doris Klingelhöfer
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Jan Bauer
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Michael H. Bendels
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Matthias Bundschuh
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • David Quarcoo
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Jenny Jaque
    Affiliations
    Department of Obstetrics and Gynecology, Keck School of Medicine of USC, Los Angeles, California, USA
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  • Author Footnotes
    1 These authors contributed equally to this work.
    Eileen M. Wanke
    Footnotes
    1 These authors contributed equally to this work.
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Author Footnotes
    1 These authors contributed equally to this work.
    David A. Groneberg
    Footnotes
    1 These authors contributed equally to this work.
    Affiliations
    Division of Social Medicine and Epidemiology, Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University, Frankfurt, Germany
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  • Author Footnotes
    1 These authors contributed equally to this work.
Published:November 15, 2017DOI:https://doi.org/10.1016/j.rbmo.2017.10.112

      Abstract

      Uterine fibroids can severely impact a woman’s quality of life, result in significant morbidity and are a leading indication for hysterectomy. Many aspects of the disease remain largely obscure. Despite these knowledge gaps, no detailed maps of the global fibroid research architecture have yet been generated. This study used the NewQIS approach to assess worldwide research productivity, encompassing numerous aspects of the scientific output, quality and socioeconomic features. Regression analysis indicated an increase in fibroid research activity in the investigated time periods. Global research output was dominated by leading Western countries, with the USA at the forefront, but also by East Asian countries. Socioeconomic benchmarking revealed that Taiwan had the highest fibroid research activity per GDP, with a calculated average of 279.46 fibroid-related publications per 1000 billion USD GDP. Finland was the most active country with respect to research activity per population size. Subject area analyses revealed major differences in research focuses, for example ‘Radiology, Nuclear Medicine and Medical Imaging’ was assigned to 29.92% of South Korean and to only 10.38% of US-American publications. In conclusion, this analysis of global fibroid research activity illustrates a multitude of important features ranging from quantitative and semi-qualitative fibroid research aspects to socioeconomic benchmarking.

      Keywords

      Introduction

      Uterine fibroids or leiomyomas represent the most common benign tumour of the female genital tract (
      • Downes E.
      • Sikirica V.
      • Gilabert-Estelles J.
      • Bolge S.C.
      • Dodd S.L.
      • Maroulis C.
      • Subramanian D.
      The burden of uterine fibroids in five european countries.
      ,
      • Lumsden M.A.
      • Hamoodi I.
      • Gupta J.
      • Hickey M.
      Fibroids: diagnosis and management.
      ,
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ). Matthew Baille first described these monoclonal tumours originating from uterine myometrium, in 1793 (
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ). A woman over 45 years of age has a fibroid lifetime risk of more than 60% as estimated in longitudinal studies (
      • Okolo S.
      Incidence, aetiology and epidemiology of uterine fibroids.
      ). However, the accurate prevalence of fibroids is largely unknown because the majority remain asymptomatic and undiagnosed. In a population-based study conducted in the USA, 51% of randomly selected premenopausal women with no previous history of myomas received an ultrasound-based diagnosis of uterine fibroids (
      • Baird D.D.
      • Dunson D.B.
      • Hill M.C.
      • Cousins D.
      • Schectman J.M.
      High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence.
      ). The incidence of leiomyomas is up to three-fold greater in black women, who develop these tumours at earlier ages than white females (
      • Baird D.D.
      • Dunson D.B.
      • Hill M.C.
      • Cousins D.
      • Schectman J.M.
      High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence.
      ). Uterine fibroids become clinically apparent in only up to 40% of women aged 40 years and over (
      • Okolo S.
      Incidence, aetiology and epidemiology of uterine fibroids.
      ). Also, their incidence based on histology is more than twice the clinical incidence (
      • Okolo S.
      Incidence, aetiology and epidemiology of uterine fibroids.
      ,
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ). Leiomyomas cause significant morbidity due to abnormal uterine bleeding and pelvic pressure symptoms. Hence, they have great impact on the quality of life of many women and the healthcare system in general (
      • Okolo S.
      Incidence, aetiology and epidemiology of uterine fibroids.
      ,
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ).
      Recently published reviews concluded that more research is necessary to determine the risk factors associated with fibroid onset and growth (
      • Commandeur A.E.
      • Styer A.K.
      • Teixeira J.M.
      Epidemiological and genetic clues for molecular mechanisms involved in uterine leiomyoma development and growth.
      ,
      • Drayer S.M.
      • Catherino W.H.
      Prevalence, morbidity, and current medical management of uterine leiomyomas.
      ). Also, no clear insight into uterine fibroid epidemiology has yet been achieved. Future research into the genetic background and modifiable risk factors may shed light on fibroid prevention and provide new approaches to non-surgical and surgical fibroid treatment (
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ,
      • Yang Q.
      • Diamond M.P.
      • Al-Hendy A.
      Early life adverse environmental exposures increase the risk of uterine fibroid development: role of epigenetic regulation.
      ). It is for these reasons, as well as the high myoma prevalence, that further multidisciplinary, translational and clinical research is needed. To plan new research strategies and to supply decision-makers with information concerning funding strategies, scientometric approaches may be of help for uterine fibroid research. It is therefore the objective of the present study to assess scientific performance in the field of uterine fibroid research over the past century using the tools of the ‘New Quality and Quantity Indices in Science’ (NewQIS) platform (
      • Groneberg-Kloft B.
      • Fischer T.C.
      • Quarcoo D.
      • Scutaru C.
      New quality and quantity indices in science (newqis): the study protocol of an international project.
      ,
      • Groneberg-Kloft B.
      • Quarcoo D.
      • Scutaru C.
      Quality and quantity indices in science: use of visualization tools.
      ). The project combines scientometric tools and advanced density-equalizing mapping procedures (
      • Gastner M.T.
      • Newman M.E.
      Diffusion-based method for producing density-equalizing maps.
      ) to assess the global uterine fibroid research architecture.

      Materials and methods

      NewQIS protocol

      The present study was facilitated by the NewQIS platform (
      • Groneberg-Kloft B.
      • Fischer T.C.
      • Quarcoo D.
      • Scutaru C.
      New quality and quantity indices in science (newqis): the study protocol of an international project.
      ,
      • Groneberg-Kloft B.
      • Quarcoo D.
      • Scutaru C.
      Quality and quantity indices in science: use of visualization tools.
      ). We established this computing platform in 2009 as an international, multidisciplinary project, and it has been used to assess more than 50 different biomedical entities to date. The NewQIS platform approach encompasses advanced visualization algorithms such as Gastner and Newman's density-equalizing calculations, indices modified for country-specific contributions to the current body of literature based on the concept of the Hirsch index (h-index) (
      • Hirsch J.E.
      An index to quantify an individual's scientific research output.
      ,
      • Hirsch J.E.
      Does the h index have predictive power?.
      ) and other scientometric tools in order to evaluate and visualize uterine fibroid-specific research activity (
      • Groneberg-Kloft B.
      • Klingelhoefer D.
      • Zitnik S.E.
      • Scutaru C.
      Traffic medicine-related research: a scientometric analysis.
      ,
      • Kusma B.
      • Scutaru C.
      • Quarcoo D.
      • Welte T.
      • Fischer T.C.
      • Groneberg-Kloft B.
      Tobacco control: visualisation of research activity using density-equalizing mapping and scientometric benchmarking procedures.
      ,
      • Vitzthum K.
      • Scutaru C.
      • Musial-Bright L.
      • Quarcoo D.
      • Welte T.
      • Spallek M.
      • Groneberg-Kloft B.
      Scientometric analysis and combined density-equalizing mapping of environmental tobacco smoke (ets) research.
      ).

      Data source and search algorithms

      The Web of Science database (WoS, Thomson Scientific) was employed for data collection as described in previous NewQIS studies (
      • Gerber A.
      • Klingelhoefer D.
      • Groneberg D.
      • Bundschuh M.
      Antineutrophil cytoplasmic antibody-associated vasculitides: a scientometric approach visualizing worldwide research activity.
      ,
      • Koster C.
      • Klingelhöfer D.
      • Groneberg D.A.
      • Schwarzer M.
      Rotavirus–global research density equalizing mapping and gender analysis.
      ). The following search strategy was used to identify fibroid-related research data: fibroid* OR fibroma* OR fibromyoma* OR leiomyoma* OR myoma* [Title] and uteri* OR uterus OR myometr* OR myomectom* OR hysterectomy OR GnRH OR emboli*ation OR *fertil* OR reproduct* OR pregnan* OR abort* OR miscarriage* OR pelvi* OR gynecolog* OR obstetric* OR menorrhagia OR bleeding OR anemia OR oestrogen OR steroid* OR *menopaus* OR black OR afroamerica* OR nullipar* OR submucous OR intramural OR subsero* OR intracavitar* OR cervi* [Topic] NOT cutan* OR skin OR *esophag* OR gastr* OR gallbladder OR liver OR spine [Title] NOT ‘gastrointestinal bleed*’ OR ‘GI bleed*’ OR ‘rectal bleed*’ OR ‘vaginal leiomyoma*’ OR *nasal OR ‘*vascular leiomyoma*’ OR ‘jejunal leiomyoma*’ OR ‘duodenal leiomyoma*’ OR ‘leiomyoma* of the duodenum’ OR ‘leiomyoma* of the jejunum’ OR appendiceal leiomyoma OR ‘intestinal leiomyoma*’ OR ‘Leiomyoma* of the urinary bladder’ OR ‘bladder leiomyoma*’ OR urethral leiomyoma OR ‘cardi* leiomyoma*’ OR ‘cardi* fibroma*’ OR chondromyxoid OR fibromatosis OR ‘leiomyoma of the breast’ OR ‘skin leiomyoma*’ OR ‘*esophag* leiomyoma*’ OR ‘gastr* leiomyoma*’ OR ‘colon* leiomyoma*’ OR ‘benign metastasizing leiomyoma*’ OR ‘mesosalphinx leiomyoma*’ OR ‘fibroma* of the jaw*’ OR odontogenic OR ‘Collagenous Fibroma*’ OR ‘Nuchal Fibroma*’ OR ‘leiomyoma of the vulva’ OR ‘soft tissue leiomyoma’ OR male OR ‘black bear’ OR ‘Colon* Polyp’ OR ‘endocardial fibroma*’ OR ‘*pharyngeal fibroma*’ OR ‘ventricular fibroma’ OR ‘pulmonary emboli*ation’ OR ‘ovar* leiomyoma*’ OR ‘ovar* fibroma*’ OR bone [Topic].
      The search covered the time period between 1900 and 2015. This search term was entered in the WoS as described previously for other areas of medicine (
      • Groneberg D.A.
      • Braun M.
      • Klingelhoefer D.
      • Bundschuh M.
      • Gerber A.
      Pancreatitis: global research activities and gender imbalances: a scientometric approach using density-equalizing mapping.
      ,
      • Quarcoo D.
      • Brüggmann D.
      • Klingelhöfer D.
      • Groneberg D.A.
      Ebola and its global research architecture – need for an improvement.
      ,
      • Scutaru C.
      • Quarcoo D.
      • Takemura M.
      • Welte T.
      • Fischer T.C.
      • Groneberg-Kloft B.
      Density-equalizing mapping and scientometric benchmarking in industrial health.
      ). All document types were included in the analysis.

      Data analysis and categorization

      As previously described, retrieval of the metadata with exact bibliographic details of all uterine fibroid-related publications was followed by numerous sorting and analysing steps (
      • Groneberg D.A.
      • Rahimian S.
      • Bundschuh M.
      • Schwarzer M.
      • Gerber A.
      • Kloft B.
      Telemedicine–a scientometric and density equalizing analysis.
      ,
      • Ohlendorf D.
      • Schwarze B.
      • Groneberg D.A.
      • Schwarzer M.
      [Magnetic resonance imaging. Density equalizing mapping analysis of global research architecture].
      ,
      • Scutaru C.
      • Quarcoo D.
      • Takemura M.
      • Welte T.
      • Fischer T.C.
      • Groneberg-Kloft B.
      Density-equalizing mapping and scientometric benchmarking in industrial health.
      ). These steps included analysis for originating countries, languages, document types, citations, cited references, year published and subject categories. Then, amongst other things, research-specific, country-specific h-indices were constructed. The h-index was developed by Jorge Hirsch in 2005 in order to gauge the quality attributed to the scientific achievement of single authors (
      • Hirsch J.E.
      An index to quantify an individual's scientific research output.
      ,
      • Hirsch J.E.
      Does the h index have predictive power?.
      ). The concept was used here particularly to assess country-specific uterine fibroid research, as described previously for other diseases (
      • Groneberg-Kloft B.
      • Fischer T.C.
      • Quarcoo D.
      • Scutaru C.
      New quality and quantity indices in science (newqis): the study protocol of an international project.
      ,
      • Groneberg-Kloft B.
      • Quarcoo D.
      • Scutaru C.
      Quality and quantity indices in science: use of visualization tools.
      ,
      • Hirsch J.E.
      An index to quantify an individual's scientific research output.
      ).

      Economic analysis

      In order to assess the relative contributions of highly active nations in uterine fibroid research with regard to their socioeconomic status and financial resources, the national gross domestic product (GDP) was related to the country-specific uterine fibroid research activities. Economic facts and the classification of countries according to their income were obtained from the World Factbook ().

      Density-equalizing mapping procedures

      The core technique of the NewQIS program consists of an algorithm that generates world maps visualizing quantitative and qualitative assessments in a specific research area (
      • Groneberg-Kloft B.
      • Kreiter C.
      • Welte T.
      • Fischer A.
      • Quarcoo D.
      • Scutaru C.
      Interfield dysbalances in research input and output benchmarking: visualisation by density equalizing procedures.
      ,
      • Groneberg-Kloft B.
      • Scutaru C.
      • Kreiter C.
      • Kolzow S.
      • Fischer A.
      • Quarcoo D.
      Institutional operating figures in basic and applied sciences: scientometric analysis of quantitative output benchmarking.
      ,
      • Kusma B.
      • Scutaru C.
      • Quarcoo D.
      • Welte T.
      • Fischer T.C.
      • Groneberg-Kloft B.
      Tobacco control: visualisation of research activity using density-equalizing mapping and scientometric benchmarking procedures.
      ,
      • Vitzthum K.
      • Scutaru C.
      • Musial-Bright L.
      • Quarcoo D.
      • Welte T.
      • Spallek M.
      • Groneberg-Kloft B.
      Scientometric analysis and combined density-equalizing mapping of environmental tobacco smoke (ets) research.
      ). In the present study, fibroid research-specific world maps were generated using density-equalizing mapping procedures (DEMP): after transfer of the metadata to Excel charts and parameter analysis, uterine fibroid-specific DEMPs were created based on methods previously published by
      • Gastner M.T.
      • Newman M.E.
      Diffusion-based method for producing density-equalizing maps.
      . The territories of the different fibroid research-publishing countries were separated from each other and resized in proportion to the selected fibroid research-specific variable of interest (i.e. country-specific h-indices).

      Analysis of uterine fibroid research collaborations

      To analyse national and international research collaborations, all affiliations of authors that published fibroid-specific publications were collected and investigated as previously described for other diseases (
      • Carl J.
      • Schwarzer M.
      • Klingelhoefer D.
      • Ohlendorf D.
      • Groneberg D.A.
      Curare – a curative poison: a scientometric analysis.
      ). A relationship of two authors was identified as a collaboration if they worked in different countries and contributed to the same publication. A chart diagram was constructed with vectors representing the quantity of the collaborative work by their width and shade of grey.

      Results

      Density-equalizing mapping

      Between 1900 and 2015 a total of 6176 documents related to uterine fibroids were identified. The first 20 publications were authored in 1900. From the 1990s to the new millennium, around 100 publications were published each year. After 2002 this number increased to more than 200 articles per year, and from 2013 onwards more than 300 articles per year were authored (Figure 1A). Regression analysis from 1970 to 2015 identified an r2 value of 0.91. In the country-specific analysis, authors from 95 countries participated in uterine fibroid research with scientists from the USA displaying the highest fibroid research activity (n = 2185 fibroid-related publications). They were followed by the UK with n = 411 publications, Japan (n = 407), Germany (n = 310), Italy (n = 309), China (n = 243), France (n = 207), Canada (n = 152), Taiwan (n = 148) and South Korea (n = 137) (Figure 1B). DEMP analysis visualized the research activity of individual countries by the distortion of the global map with a focus on North America, Europe and Far East Asia including Japan, China, Taiwan and South Korea (Figure 1B).
      Figure 1
      Figure 1Density-equalizing map of global uterine fibroid research activity. (A) Number of publications. (B) Number of published items per year.
      The total citation analysis indicated a leading position of the USA with a total of n = 41,524 citations related to fibroid-specific publications. This was followed by the UK (n = 6984) and Japan (n = 5974) (Figure 2A). Fibroid-specific h-index analysis for each country also showed a leading position of the USA with an h-index of 92, meaning that 92 fibroid-related publications authored by US-American scientists were being cited at least 92 times. The USA was followed by the UK (h-index = 44), Japan and Italy (h-index = 40 each) (Figure 2B). The average citation number per fibroid publication attributed to every country investigated was analysed. This number was termed the citation rate (cr). Countries that published fewer than 30 myoma publications were excluded from this particular analysis. In the cr ranking, Sweden was leading the field with a cr of 22.78, followed by Finland (cr = 21.95). The USA had a cr of 19.00 and articles from the UK received 16.99 average citations per publication (Figure 2C).
      Figure 2
      Figure 2Density-equalizing maps of global uterine fibroid research quality. (A) Total number of fibroid-specific citations per country. (B) Fibroid-specific h-indices. (C) Fibroid-specific citation rates (threshold of 30 publications per country).

      Socioeconomic analysis of uterine fibroid research

      In order to assess uterine fibroid research activities with regard to the socioeconomic status of a country, the GDP of each country in 1000 billion (bn) USD was used, serving as a proxy measure for total economic strength and resources that can be dedicated to research. Among high-income countries, Taiwan was ranked first with 148 uterine fibroid-related research papers and a calculated average of 279.46 fibroid-related publications per 1000 bn USD GDP (RGDP). It was followed by Israel (RGDP = 266.62), and Finland (RGDP = 243.36) (Table 1). The UK had an RGDP = 139.56, and the USA reached an RGDP of 125.43. Turkey was identified as the upper middle-income country with the highest RGDP (169.95) whereas China had a RGDP value of 23.41.
      Table 1Socioeconomic analysis of fibroid research of the most active countries.
      CountryNo. of articlesGDP in 1000 bn USDGDP per capitaPopulation total in mill.Articles/GDP in 1000 bn USDRanking 1Articles/GDP per capitaRanking 2Articles/population in mill.Ranking 3
      Finland660.271240.55.26243.36HI31.63HI1912.55HI1
      Israel810.303833.47.82266.62HI22.43HI1210.36HI2
      Sweden770.570144.79.72135.06HI81.72HI187.92HI3
      Belgium720.534741.710.44134.65HI91.73HI176.90HI4
      USA218517.4254.8318.9125.43HI1039.87HI16.85HI5
      UK4112.94537.763.74139.56HI710.90HI26.45HI6
      Taiwan1480.529643.623.35279.46HI13.39HI106.34HI7
      Switzerland480.712155.28.0667.41HI200.87HI215.96HI8
      Netherlands1000.866447.416.87115.42HI122.11HI145.93HI9
      Italy3092.14834.561.68143.85HI68.96HI45.01HI10
      Australia1061.44446.622.573.41HI182.27HI134.71HI11
      Denmark260.340844.35.5676.29HI170.59HI234.68HI12
      Greece490.23825.810.77205.88HI41.90HI164.55HI13
      Canada1521.78944.534.8384.96HI153.42HI84.36HI14
      Germany3103.8644.780.9980.31HI166.94HI53.83HI15
      Austria290.437145.48.2266.35HI210.64HI223.53HI16
      Japan4074.61637.8127.188.17HI1410.77HI33.20HI17
      France2072.84740.466.2572.71HI195.12HI63.12HI18
      South Korea1371.4135.449.0397.16HI133.87HI72.79HI19
      Czech Republic250.205728.410.62121.54HI110.88HI202.35HI20
      Poland830.546624.438.34151.85HI53.40HI92.16HI20
      Spain931.4073347.7366.10HI222.82HI111.95HI21
      Turkey1370.806119.681.61169.95UMI16.99UMI21.68UMI1
      South Africa320.350112.748.3791.40UMI22.52UMI40.66UMI2
      Brazil862.35315.2202.636.55UMI45.66UMI30.42UMI3
      Russia481.85724.8142.4725.85HI231.94HI150.34HI22
      Egypt270.286411.186.8994.27LMI12.43LMI20.31LMI1
      Iran250.404116.580.8461.87UMI31.52UMI50.31UMI4
      China24310.3812.91355.723.41UMI518.84UMI10.18UMI5
      India982.055.81236.347.80LMI216.90LMI10.08LMI2
      Sources for GDP (current prices in 1000 bn US dollars) and GDP per capita (current prices in 1000 US dollars): International Monetary Fund.
      HI = high-income country; LMI = lower middle-income country; UMI = upper middle-income country.
      Threshold 25 fibroid-related publications.
      Also, the country-specific uterine fibroid publications were related to the population size. Here, Finland was the most active high-income country with 12.55 publications per million inhabitants (Rpop), followed by Israel (Rpop = 10.36), Sweden (Rpop = 7.92), Belgium (Rpop = 6.90) and the USA (Rpop = 6.85) (Figure 3A). In the upper middle-income country ranking, Turkey was ranked in first position with an Rpop of 1.68, followed by South Africa (0.66). China had an Rpop of 0.18 (Table 1). When the economic strength of a country was analysed using the GDP in bn USD per capita (Rpc), the USA was ranked as the first high-income country with an index of Rpc = 39.87, followed by the UK (Rpc = 10.90) and Japan (Rpc = 10.77) (Figure 3B, Table 1).
      Figure 3
      Figure 3Density-equalizing maps of global uterine fibroid research socioeconomic figures. (A) Publications/population in mill. (B) Publications/GDP in 1000 billion (bn) USD, threshold: ≥ 30 specific publications.

      Fibroid research subject area analysis

      In the past two decades, the leading subject categories of uterine fibroid research included ‘Obstetrics and Gynecology’, ‘Reproductive Biology’ and ‘Radiology, Nuclear Medicine and Medical Imaging’. Between 1966 and 2015, the chronological development of the subject areas was analysed in greater detail: we noted a prominent increase in the publication number in the field of ‘Reproductive Biology’, with a growth of 17.1% between 1986 and 1990 and of 23.4% between 2011 and 2015. It was striking that ‘Public Health’ did not belong to the most active subject areas in myoma research (Figure 4A). When subject area analysis was conducted for highly active uterine fibroid research countries, major differences were found for the field of ‘Radiology, Nuclear Medicine and Medical Imaging’. Here, South Korea's proportion totalled 29.92% while only 10.38% of publications dedicated to this area were attributed to the USA (Figure 4B).
      Figure 4
      Figure 4Subject area analysis of uterine fibroid research. (A) Relative proportions of the most assigned subject areas in five-year intervals between 1965 and 2014. (B) Proportions of the most assigned subject areas in most active countries.

      International uterine fibroid collaborations

      In total, 476 international collaborations (n) contributed to the 6176 overall publications. The USA was the most active country, participating in 268 collaborative relationships representing 56.3% of all international collaborations. The USA was followed by the UK, with n = 91 collaborations, Italy (n = 73) and Germany (n = 72), respectively. The most common bilateral collaborations were found between US-American scientists and their Italian, Canadian and German counterparts (Figure 5).
      Figure 5
      Figure 5Uterine fibroid research collaborations between countries. Numbers in brackets (publication numbers/number of collaborative publications), threshold: ≥ 20 collaborations of a single country.

      Number of institutions per country

      The number of institutions per country devoted to uterine fibroid research was also analysed using DEMP techniques. Figure 6 illustrates that 720 different US-American institutions participated in fibroid research. The USA was followed by Japan (224 institutions), the UK (211 institutions), Germany (165 institutions), Italy (161 institutions) and France (155 institutions). In China, 142 institutions were working on uterine fibroid research (Figure 6).
      Figure 6
      Figure 6Density-equalizing mapping of institutions. Total number of fibroid research-performing institutions per country.

      Discussion

      Uterine fibroids represent the most common benign tumours of the female reproductive system. They cause significant morbidity and deterioration in the quality of life of many women worldwide (
      • Downes E.
      • Sikirica V.
      • Gilabert-Estelles J.
      • Bolge S.C.
      • Dodd S.L.
      • Maroulis C.
      • Subramanian D.
      The burden of uterine fibroids in five european countries.
      ,
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ). It has been estimated that about 40–60% of all hysterectomies are due to the presence of uterine fibroids (
      • Fleischer R.
      • Weston G.C.
      • Vollenhoven B.J.
      • Rogers P.A.
      Pathophysiology of fibroid disease: Angiogenesis and regulation of smooth muscle proliferation.
      ,
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ). The pathophysiology of myomas is still largely obscure, with altered smooth muscle cell proliferation and disordered angiogenesis playing prominent roles (
      • Fleischer R.
      • Weston G.C.
      • Vollenhoven B.J.
      • Rogers P.A.
      Pathophysiology of fibroid disease: Angiogenesis and regulation of smooth muscle proliferation.
      ). Because the cause of uterine fibroids remains unclear and their biology is poorly understood (
      • Okolo S.
      Incidence, aetiology and epidemiology of uterine fibroids.
      ), new research efforts are needed. Therefore, this analysis was performed to present preliminary data on the global background of fibroid research over the past century. In contrast to the numerous studies already existing for OB/GYN entities such as endometriosis (
      • Brüggmann D.
      • Elizabeth-Martinez A.
      • Klingelhöfer D.
      • Quarcoo D.
      • Jaque J.M.
      • Groneberg D.A.
      Endometriosis and its global research architecture: an in-depth density-equalizing mapping analysis.
      ,
      • Brüggmann D.
      • Richter T.
      • Klingelhöfer D.
      • Gerber A.
      • Bundschuh M.
      • Jaque J.
      • Groneberg D.A.
      Global architecture of gestational diabetes research: density-equalizing mapping studies and gender analysis.
      ), Caesarean section (
      • Brüggmann D.
      • Lohlein L.K.
      • Louwen F.
      • Quarcoo D.
      • Jaque J.
      • Klingelhöfer D.
      • Groneberg D.A.
      Caesarean section – a density-equalizing mapping study to depict its global research architecture.
      ), gestational diabetes (
      • Brüggmann D.
      • Elizabeth-Martinez A.
      • Klingelhöfer D.
      • Quarcoo D.
      • Jaque J.M.
      • Groneberg D.A.
      Endometriosis and its global research architecture: an in-depth density-equalizing mapping analysis.
      ,
      • Brüggmann D.
      • Richter T.
      • Klingelhöfer D.
      • Gerber A.
      • Bundschuh M.
      • Jaque J.
      • Groneberg D.A.
      Global architecture of gestational diabetes research: density-equalizing mapping studies and gender analysis.
      ), breast cancer (
      • Glynn R.W.
      • Scutaru C.
      • Kerin M.J.
      • Sweeney K.J.
      Breast cancer research output, 1945–2008: a bibliometric and density-equalizing analysis.
      ,
      • Healy N.A.
      • Glynn R.W.
      • Scutaru C.
      • Groneberg D.
      • Kerin M.J.
      • Sweeney K.J.
      The h index and the identification of global benchmarks for breast cancer research output.
      ) or polycystic ovary syndrome (
      • Brüggmann D.
      • Berges L.
      • Klingelhöfer D.
      • Bauer J.
      • Bendels M.
      • Louwen F.
      • Jaque J.
      • Groneberg D.A.
      Polycystic ovary syndrome: analysis of the global research architecture using density equalizing mapping.
      ,
      • Brüggmann D.
      • Pulch K.
      • Klingelhöfer D.
      • Pearce C.L.
      • Groneberg D.A.
      Ovarian cancer: density equalizing mapping of the global research architecture.
      ,
      • Brüggmann D.
      • Wagner C.
      • Klingelhöfer D.
      • Schoffel N.
      • Bendels M.
      • Louwen F.
      • Jaque J.
      • Groneberg D.A.
      Maternal depression research: socioeconomic analysis and density-equalizing mapping of the global research architecture.
      ), detailed density-equalizing maps do not yet exist for the field of uterine fibroid research.
      We want to address some limitations before discussing the main findings of the study: as previously stated, one limitation of this study is based upon the fact that the WoS includes predominantly journals published in the English language (
      • Brüggmann D.
      • Berges L.
      • Klingelhöfer D.
      • Bauer J.
      • Bendels M.
      • Louwen F.
      • Jaque J.
      • Groneberg D.A.
      Polycystic ovary syndrome: analysis of the global research architecture using density equalizing mapping.
      ,
      • Brüggmann D.
      • Pulch K.
      • Klingelhöfer D.
      • Pearce C.L.
      • Groneberg D.A.
      Ovarian cancer: density equalizing mapping of the global research architecture.
      ,
      • Brüggmann D.
      • Wagner C.
      • Klingelhöfer D.
      • Schoffel N.
      • Bendels M.
      • Louwen F.
      • Jaque J.
      • Groneberg D.A.
      Maternal depression research: socioeconomic analysis and density-equalizing mapping of the global research architecture.
      ). Therefore, non-English articles may be under-represented in our search. However, scientists usually publish their high-quality research in English journals, which limits this particular bias. Another bias is linked to our investigated parameters based on citation counts. High citation numbers are believed to reflect high scientific quality. However, this relationship is biased by the so-called Matthew effect (
      • Merton R.K.
      The matthew effect in science. The reward and communication systems of science are considered.
      ): publications by renowned scientists will be cited more than works by lesser known scientists. Boosted mainly by the author's popularity in the field, the citation count of these papers increases exponentially right after publication (
      • Merton R.K.
      The matthew effect in science. The reward and communication systems of science are considered.
      ).
      From a historical perspective, general uterine fibroid research activity over the past decades develops similarly to other areas of science. We identified only minimal scientific activity until the 1970s. During the following two decades, a strong increase in research productivity was noted. Publication numbers in the field have increased dramatically since the late 1990s and reached the striking output of 300 annual publications after 2013. Interestingly, the nature of uterine fibroid research differs from other gynaecological disorders. This can be concluded from the subject area analysis, in which a large percentage of publications was attributed to subject areas such as ‘radiology’, whereas public health issues were of limited interest. By contrast, researchers in ‘gestational diabetes’ or ‘caesarean section’ also dedicated their scientific activity to the important field of ‘Public Health’ (
      • Brüggmann D.
      • Lohlein L.K.
      • Louwen F.
      • Quarcoo D.
      • Jaque J.
      • Klingelhöfer D.
      • Groneberg D.A.
      Caesarean section – a density-equalizing mapping study to depict its global research architecture.
      ,
      • Brüggmann D.
      • Elizabeth-Martinez A.
      • Klingelhöfer D.
      • Quarcoo D.
      • Jaque J.M.
      • Groneberg D.A.
      Endometriosis and its global research architecture: an in-depth density-equalizing mapping analysis.
      ,
      • Brüggmann D.
      • Richter T.
      • Klingelhöfer D.
      • Gerber A.
      • Bundschuh M.
      • Jaque J.
      • Groneberg D.A.
      Global architecture of gestational diabetes research: density-equalizing mapping studies and gender analysis.
      ). However, uterine fibroids are reported to be the most common indication for hysterectomy in the USA and Australia (
      • Fleischer R.
      • Weston G.C.
      • Vollenhoven B.J.
      • Rogers P.A.
      Pathophysiology of fibroid disease: Angiogenesis and regulation of smooth muscle proliferation.
      ,
      • Sparic R.
      • Mirkovic L.
      • Malvasi A.
      • Tinelli A.
      Epidemiology of uterine myomas: a review.
      ) and burden many women around the globe by affecting their quality of life. Hence, we underline the imminent need to target this tumour by interventions in the field of public health. Funding agencies may pay specific attention to grant proposals in this area focusing on organized efforts raising awareness and implementing interventions within the society, organizations or the community.
      From a country-specific viewpoint, the pattern of uterine fibroid research productivity largely parallels research activity in other areas of biomedical sciences (
      • Groneberg-Kloft B.
      • Kreiter C.
      • Welte T.
      • Fischer A.
      • Quarcoo D.
      • Scutaru C.
      Interfield dysbalances in research input and output benchmarking: visualisation by density equalizing procedures.
      ,
      • Groneberg-Kloft B.
      • Scutaru C.
      • Kreiter C.
      • Kolzow S.
      • Fischer A.
      • Quarcoo D.
      Institutional operating figures in basic and applied sciences: scientometric analysis of quantitative output benchmarking.
      ). High-income countries – the USA in particular – are leaders in the field of uterine fibroid research. This finding is not surprising due to the surgical (i.e. novel approaches) and technical (i.e. diagnostic) equipment required for the medical care of leiomyoma patients and related research, which is dependent on a high level of industrialization (‘high tech’). Within our study, a particularly outstanding position was occupied by the USA. Besides its dominance regarding the overall research activity related to myomas, the USA was also found in the leading position when analyses of the total citation count or the country-specific h-indices were performed. We attribute this prominent role of the USA to the outstanding overall resources this country attributes to research and development in general, e.g. 2.7% of its GDP in 2013 (http://databank.worldbank.org/data/reports.aspx?source=2&series=GB.XPD.RSDV.GD.ZS&country) supporting the highest number of institutions working on fibroids within the community. Apart from this dominant role of US-American institutions, the UK, Japan and Germany are the most active countries in fibroid research. A similar pattern was revealed in a global research output study that analysed a total of 5,527,558 publications in diverse fields of medicine (
      • Groneberg-Kloft B.
      • Kreiter C.
      • Welte T.
      • Fischer A.
      • Quarcoo D.
      • Scutaru C.
      Interfield dysbalances in research input and output benchmarking: visualisation by density equalizing procedures.
      ,
      • Groneberg-Kloft B.
      • Scutaru C.
      • Kreiter C.
      • Kolzow S.
      • Fischer A.
      • Quarcoo D.
      Institutional operating figures in basic and applied sciences: scientometric analysis of quantitative output benchmarking.
      ). The USA was found to be the most productive country with an impressive number of 1,893,800 publications. Japan ranked second with 573,473 items followed by Germany (n = 444,775) and the UK (n = 415,499) (
      • Groneberg-Kloft B.
      • Kreiter C.
      • Welte T.
      • Fischer A.
      • Quarcoo D.
      • Scutaru C.
      Interfield dysbalances in research input and output benchmarking: visualisation by density equalizing procedures.
      ,
      • Groneberg-Kloft B.
      • Scutaru C.
      • Kreiter C.
      • Kolzow S.
      • Fischer A.
      • Quarcoo D.
      Institutional operating figures in basic and applied sciences: scientometric analysis of quantitative output benchmarking.
      ). Interestingly, many East Asian countries play an important role in the international uterine fibroid research community. These nations are represented by Japan, China, Taiwan and South Korea, which belong to the top ten most productive countries. It should be pointed out that this finding is in striking contrast to other gynaecological disorders, i.e. Caesarean section (
      • Brüggmann D.
      • Lohlein L.K.
      • Louwen F.
      • Quarcoo D.
      • Jaque J.
      • Klingelhöfer D.
      • Groneberg D.A.
      Caesarean section – a density-equalizing mapping study to depict its global research architecture.
      ).
      Overall research activity is a benchmark, which is heavily dependent on different socioeconomic features and resources. To assess the role of single countries in fibroid research in relation to their population sizes and economic welfare, NewQIS recently introduced a set of socioeconomic parameters into the analysis panel (
      • Brüggmann D.
      • Berges L.
      • Klingelhöfer D.
      • Bauer J.
      • Bendels M.
      • Louwen F.
      • Jaque J.
      • Groneberg D.A.
      Polycystic ovary syndrome: analysis of the global research architecture using density equalizing mapping.
      ,
      • Brüggmann D.
      • Pulch K.
      • Klingelhöfer D.
      • Pearce C.L.
      • Groneberg D.A.
      Ovarian cancer: density equalizing mapping of the global research architecture.
      ,
      • Brüggmann D.
      • Wagner C.
      • Klingelhöfer D.
      • Schoffel N.
      • Bendels M.
      • Louwen F.
      • Jaque J.
      • Groneberg D.A.
      Maternal depression research: socioeconomic analysis and density-equalizing mapping of the global research architecture.
      ). We reviewed international uterine fibroid research activity in context with the GDP of single countries, which was used as a proxy for the nation's capacity to invest in research. Here, Taiwan appeared to be the country with the highest fibroid research activity per 1000 bn USD, followed by Israel and Finland. Based on these results, we acknowledge a potential bias in relating the country-specific publication numbers to the current GDP but not the average GDP over the past century. However, because most of the articles were published in the past 20 years and the GDP ranking of countries had not changed significantly over time, we feel it appropriate to use the current GDP to examine our data in the context of socioeconomic resources of the investigated countries. This approach was also supported and used by numerous other authors working in the bibliometric field (
      • Badenhorst A.
      • Mansoori P.
      • Chan K.Y.
      Assessing global, regional, national and sub-national capacity for public health research: a bibliometric analysis of the Web of Science (TM) in 1996–2010.
      ,
      • Phillips K.
      • Kohler J.C.
      • Pennefather P.
      • Thorsteinsdottir H.
      • Wong J.
      Canada's neglected tropical disease research network: who's in the core-who's on the periphery?.
      ,
      • Sweileh W.M.
      • AbuTaha A.S.
      • Sawalha A.F.
      • Al-Khalil S.
      • Al-Jabi S.W.
      • Zyoud S.H.
      Bibliometric analysis of worldwide publications on multi-, extensively, and totally drug - resistant tuberculosis (2006-2015).
      ,
      • Zyoud S.H.
      Bibliometric analysis on global Catha edulis (khat) research production during the period of 1952–2014.
      ).
      When the scientific productivity of a single nation was related to its population size, Finland, Israel and Sweden were found to occupy the top positions. This pattern of Scandinavian countries in prominent positions was also replicated in the analysis of (semi)-qualitative aspects of fibroid research, e.g. the citation rate (cr, the average citations per fibroid publication). Here, Sweden was leading with 22.78 citations per article, followed by Finland (cr = 21.95). Altogether, this finding indicates that the relatively small Scandinavian nations have established effective and efficient research structures that produce high-quality science. This not only applies to Sweden, the traditional host of the Nobel prizes (
      • Pernow B.
      [The first three nordic nobel laureates in physiology or medicine].
      ), but also to Finland and Denmark.
      When the network of international collaborations was analysed, it was apparent that 7.7% of collaborative articles out of all research publications on myomas (n = 476 out of 6176 fibroid-specific publications) is a rather low rate compared with other fields in gynaecology. We postulate that this finding can be explained by the benign nature of the tumour and the abundance of patients and available specimens, which do not require the performance of complex multinational studies with a focus on chemotherapy, genetic backgrounds, etc. or to establish research networks to share resources. In other fields such as ovarian carcinoma, there are many large international multicentre studies and multinational networks, e.g. the Ovarian Cancer Association Consortium, which translate into prolific, collaborative and high-quality research activities connecting scientists around the globe (
      • Pearce C.L.
      • Templeman C.
      • Rossing M.A.
      • Lee A.
      • Near A.M.
      • Webb P.M.
      • Nagle C.M.
      • Doherty J.A.
      • Cushing-Haugen K.L.
      • Wicklund K.G.
      • Chang-Claude J.
      • Hein R.
      • Lurie G.
      • Wilkens L.R.
      • Carney M.E.
      • Goodman M.T.
      • Moysich K.
      • Kjaer S.K.
      • Hogdall E.
      • Jensen A.
      • Goode E.L.
      • Fridley B.L.
      • Larson M.C.
      • Schildkraut J.M.
      • Palmieri R.T.
      • Cramer D.W.
      • Terry K.L.
      • Vitonis A.F.
      • Titus L.J.
      • Ziogas A.
      • Brewster W.
      • Anton-Culver H.
      • Gentry-Maharaj A.
      • Ramus S.J.
      • Anderson A.R.
      • Brueggmann D.
      • Fasching P.A.
      • Gayther S.A.
      • Huntsman D.G.
      • Menon U.
      • Ness R.B.
      • Pike M.C.
      • Risch H.
      • Wu A.H.
      • Berchuck A.
      Association between endometriosis and risk of histological subtypes of ovarian cancer: a pooled analysis of case-control studies.
      ,
      • Shen H.
      • Fridley B.L.
      • Song H.
      • Lawrenson K.
      • Cunningham J.M.
      • Ramus S.J.
      • Cicek M.S.
      • Tyrer J.
      • Stram D.
      • Larson M.C.
      • Kobel M.
      • Ziogas A.
      • Zheng W.
      • Yang H.P.
      • Wu A.H.
      • Wozniak E.L.
      • Woo Y.L.
      • Winterhoff B.
      • Wik E.
      • Whittemore A.S.
      • Wentzensen N.
      • Weber R.P.
      • Vitonis A.F.
      • Vincent D.
      • Vierkant R.A.
      • Vergote I.
      • Van Den Berg D.
      • Van Altena A.M.
      • Tworoger S.S.
      • Thompson P.J.
      • Tessier D.C.
      • Terry K.L.
      • Teo S.H.
      • Templeman C.
      • Stram D.O.
      • Southey M.C.
      • Sieh W.
      • Siddiqui N.
      • Shvetsov Y.B.
      • Shu X.O.
      • Shridhar V.
      • Wang-Gohrke S.
      • Severi G.
      • Schwaab I.
      • Salvesen H.B.
      • Rzepecka I.K.
      • Runnebaum I.B.
      • Rossing M.A.
      • Rodriguez-Rodriguez L.
      • Risch H.A.
      • Renner S.P.
      • Poole E.M.
      • Pike M.C.
      • Phelan C.M.
      • Pelttari L.M.
      • Pejovic T.
      • Paul J.
      • Orlow I.
      • Omar S.Z.
      • Olson S.H.
      • Odunsi K.
      • Nickels S.
      • Nevanlinna H.
      • Ness R.B.
      • Narod S.A.
      • Nakanishi T.
      • Moysich K.B.
      • Monteiro A.N.
      • Moes-Sosnowska J.
      • Modugno F.
      • Menon U.
      • McLaughlin J.R.
      • McGuire V.
      • Matsuo K.
      • Adenan N.A.
      • Massuger L.F.
      • Lurie G.
      • Lundvall L.
      • Lubinski J.
      • Lissowska J.
      • Levine D.A.
      • Leminen A.
      • Lee A.W.
      • Le N.D.
      • Lambrechts S.
      • Lambrechts D.
      • Kupryjanczyk J.
      • Krakstad C.
      • Konecny G.E.
      • Kjaer S.K.
      • Kiemeney L.A.
      • Kelemen L.E.
      • Keeney G.L.
      • Karlan B.Y.
      • Karevan R.
      • Kalli K.R.
      • Kajiyama H.
      • Ji B.T.
      • Jensen A.
      • Jakubowska A.
      • Iversen E.
      • Hosono S.
      • Hogdall C.K.
      • Hogdall E.
      • Hoatlin M.
      • Hillemanns P.
      • Heitz F.
      • Hein R.
      • Harter P.
      • Halle M.K.
      • Hall P.
      • Gronwald J.
      • Gore M.
      • Goodman M.T.
      • Giles G.G.
      • Gentry-Maharaj A.
      • Garcia-Closas M.
      • Flanagan J.M.
      • Fasching P.A.
      • Ekici A.B.
      • Edwards R.
      • Eccles D.
      • Easton D.F.
      • Durst M.
      • du Bois A.
      • Dork T.
      • Doherty J.A.
      • Despierre E.
      • Dansonka-Mieszkowska A.
      • Cybulski C.
      • Cramer D.W.
      • Cook L.S.
      • Chen X.
      • Charbonneau B.
      • Chang-Claude J.
      • Campbell I.
      • Butzow R.
      • Bunker C.H.
      • Brueggmann D.
      • Brown R.
      • Brooks-Wilson A.
      • Brinton L.A.
      • Bogdanova N.
      • Block M.S.
      • Benjamin E.
      • Beesley J.
      • Beckmann M.W.
      • Bandera E.V.
      • Baglietto L.
      • Bacot F.
      • Armasu S.M.
      • Antonenkova N.
      • Anton-Culver H.
      • Aben K.K.
      • Liang D.
      • Wu X.
      • Lu K.
      • Hildebrandt M.A.
      • Schildkraut J.M.
      • Sellers T.A.
      • Huntsman D.
      • Berchuck A.
      • Chenevix-Trench G.
      • Gayther S.A.
      • Pharoah P.D.
      • Laird P.W.
      • Goode E.L.
      • Pearce C.L.
      Epigenetic analysis leads to identification of hnf1b as a subtype-specific susceptibility gene for ovarian cancer.
      ).
      Besides scientific databases such as the WoS, popular search engines like Google may provide useful information on uterine fibroids and related awareness in the general population. In this respect, a recent study by
      • Brito L.G.
      • Ferriani R.A.
      • Candido-Dos-Reis F.J.
      • Nogueira A.A.
      Using a search-volume tool (google trends) to assess global interest for uterine fibroids.
      analysed global search trends for uterine fibroids on the internet using the Google Trends Search Application. The authors reported that the mean annual global search activity on fibroids decreased significantly between 2004 and 2012 (
      • Brito L.G.
      • Ferriani R.A.
      • Candido-Dos-Reis F.J.
      • Nogueira A.A.
      Using a search-volume tool (google trends) to assess global interest for uterine fibroids.
      ). In 2004, the mean annual search activity was 77.25% of the overall peak search activity and decreased to 64.41% in 2012. The countries with highest search volume were the USA, Canada, Australia, India and the UK. By contrast, the number of uterine fibroid-related websites grew during this period, from 5680 to almost 70,600 (
      • Brito L.G.
      • Ferriani R.A.
      • Candido-Dos-Reis F.J.
      • Nogueira A.A.
      Using a search-volume tool (google trends) to assess global interest for uterine fibroids.
      ). The authors concluded that a decreased relative search activity does not necessarily represent a trend towards declining popularity of the subject. Therefore, it should be noted that the overall popularity, measured by the absolute number of Google searches, actually increased from 2004 to 2012. The authors also stated that the increased number of uterine fibroid-related websites may represent the growing number of people who are burdened by the condition and therefore interested in raising awareness (
      • Brito L.G.
      • Ferriani R.A.
      • Candido-Dos-Reis F.J.
      • Nogueira A.A.
      Using a search-volume tool (google trends) to assess global interest for uterine fibroids.
      ). In our study, we see this increasing interest among the general population paralleled by a growing scientific productivity related to uterine fibroids. This is an encouraging development that needs to be further facilitated. Therefore, more resources should be dedicated to research and public health endeavours with a focus on this condition to meet the interest this disease evokes in the general public.

      Conclusions

      This study represents the first concise analysis of global uterine fibroid research activity. We assessed scientific productivity worldwide with respect to both quantitative (overall research output) and semi-qualitative aspects (citation parameters), and in context with socioeconomic features. By using these metrics, we present the first global picture of the research architecture associated with uterine fibroids and highlight potential shortcomings in the scientific landscape.

      Acknowledgements

      We thank G Volante for helpful comments. This study is part of a PhD thesis project (TB).

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      Biography

      Dörthe Brüggmann is a board-certified gynaecologist at the OB/GYN Department, Goethe-University, Frankfurt, Germany, and holds a joint position in the Division of Female Health/Prevention at the Institute of Occupational, Social and Environmental Medicine. Additionally, she serves as an Adjunct Professor in the OB/GYN Department at the USC Keck School of Medicine in Los Angeles.
      Key message
      This study represents the first global description of the uterine fibroid research landscape over the past century. The multitude of quantitative and semi-qualitative dimensions that were presently assessed demonstrates that this field of OB/GYN clearly differs from other fields and is closely related to surgical and diagnostic issues.