Cough as a symptom and a disease entity: scientometric analysis and density-equalizing calculations.

Background: Cough is a prominent symptom of many allergic diseases and a major health burden but there is little information available on the current state of research in this area.

Objectives: To analyze long-term developments in cough research and recent trends.

Methods: We searched the Thomson Reuters Web of Science databases for cough-related items published between 1900 and 2007 and analyzed the results using scientometric methods and density-equalizing calculations.

Results: We found 12 960 cough-related publications from 132 countries for the period studied. The most productive country was the United States of America (USA), followed by the United Kingdom (UK), France, Japan, Canada, and Germany. These 12 960 published items were cited 165 868 times. The average number of citations per item increased from 1976 to 1992, with peaks in 1977, 1979, 1981, 1984, 1989 and 1992. Each of these years was followed by a decrease in citation numbers. Bilateral and multilateral cooperation analysis using the radar chart technique showed a progressive increase in international co-authorship starting at the beginning of the 1990s, with a leading role by the USA and the UK.

Conclusion: We detected a marked increased in cough-related research starting in the 1990s. While the majority of data originates from the US, other countries have taken a leading position in terms of research quality (number of citations per item).