Mammography: density equalizing mapping of the global research architecture

Abstract

Background: Since mammography belongs to the most important preventive techniques in modern medicine, this study maps the related worldwide research output, which encompasses quantitative and qualitative aspects of the scientific activity and socio-economic features.

Methods: The New Quality and Quantity Indices in Science (NewQIS) computing platform identified all mammography-specific articles in the Web of Science within two time periods, from 1900 to 2014 (P1) and from 2015 to 2020 (P2), a combination of density-equalizing mapping projections (DEMP) and socio-economic benchmarking was applied for analysis.

Results: A total of 13,629 articles were retrieved. 8,744 articles were identified in P1 and 4,885 in P2. More than 100 articles were published annually since the 1980s. Regarding productivity and collaborative efforts, the United States was the leading nation in both evaluation periods. In our socioeconomic analysis, it was also ranked at the first place in P1 [72.68 mammography-related publications per GDP/capita (RGDP)]. The US was followed by the UK and Germany in P1 and by UK and India in P2. When population sizes were related to mammography research activities, Scandinavian countries and the Netherlands showed the highest research activity in P1 (e.g., Sweden: 31.89 publications per 1 million inhabitants). Gender analysis illustrated a relative dominance of female researchers in most countries with the exception of Japan.

Conclusions: The global mammography research activity over the last century is paralleled by strong international collaborative efforts and follows largely economic figures and prevalence rates but displays distinct differences in comparison to the research landscape of other biomedical entities.

Keywords: Density equalizing map; mammography; spatiotemporal analysis.

Figure 1

Global mammography research activity (1900 to 2014). Number of published items per year. Before 1960s, no considerable annual publication output was recorded so the graph starts in 1960.

Figure 2

Global scientific productivity on mammography. Density equalizing, colours and territorial sizes indicate numbers of related articles per country. (A) Global mammography research activity from 1900 until 2014 (P1). (B) Global mammography research activity from 2015 until 2020 (P2).

Figure 3

Mammography research quality as represented by the total citation number. (A) Density equalizing map of the total number of mammography-specific citations per country from 1900 until 2014 (P1). (B) Density equalizing map of the total number of mammography-specific citations per country from 2015 until 2020 (P2).

Figure 4

Mammography research quality as represented by the citation rate. (A) Density equalizing map of the total number of mammography-specific citation rates (threshold of 30 publications per country) per country from 1900 until 2014 (P1). (B) Density equalizing map of the total number of mammography-specific citation rates (threshold of 30 publications per country) per country from 2015 until 2020 (P2).

Figure 5

Subject area analysis of mammography research, evaluation period (1900 to 2014). (A) Relative proportions of the most assigned subject areas in 5-year intervals between 1965 and 2014. (B) Relative proportions of the most assigned subject areas in most active countries.

Figure 6

Main key word analysis. Analysis of key word that were attributed for a minimum of 10 times.

Figure 7

Mammography research collaborations between regions. Greyscale and bar thickness indicate intensity of collaborations, Number in brackets (total publication numbers/number of collaborative publications), Threshold: at least 5 collaborations of a single country, evaluation period (1900 to 2014).

Figure 8

Analysis of the gender of authors publishing on mammography. (A) Subject areas of articles published by authors of a respective gender. (B) Gender of authors analysed by originating country.