title: Country comparisons of human stroke research since 2001: a bibliometric study.
abstract: OBJECTIVE
  This is the first bibliometric comparison between countries of the development of stroke research over time.
  
  
  METHODS
  Clinical and epidemiological articles on stroke published 2001 to mid-2011 were identified in Science Citation Index Expanded. Article fractions, citation fractions, h-index, and international collaboration were calculated using the BibExcel software and adjusted for population size and gross domestic product.
  
  
  RESULTS
  The United States dominated with 28.7% of the sum of article fractions and 36.2% of the sum of citation fractions. The United States, Japan, the United Kingdom, and Germany together accounted for 52.1% of articles and 61.0% of citations. When adjusted for population size or gross domestic product, several small European countries, together with Israel and Taiwan, ranked the highest. Per population, there was a negative association (r=0.60) between burden of stroke (disability-adjusted life-years lost) and number of articles per population. In China, South Korea, and Singapore, the annual growth of stroke articles was more than twice the worldwide average. Whereas multinational collaboration was common within Europe and North America, it was relatively uncommon between Asian countries.
  
  
  CONCLUSIONS
  The Big 4 in scientific literature on stroke, as to both number of articles and citations, are the United States, Japan, the United Kingdom, and Germany. Many small European countries have, in relation to their size, a high scientific production. Several countries with rapidly expanding economies have very fast growth of scientific production on stroke. Our results emphasize the need for stroke research in countries with a high population burden of stroke and they highlight the role of multinational collaboration.
authors.affiliation: Riks-Stroke, Medicine, Department of Public Health and Clinical Medicine, Umeå University, 90185 Umeå, Sweden. kjell.asplund@branneriet.se
authors.forename: Kjell
authors.initials: K
authors.lastname: Asplund
authors.forename: Marie
authors.initials: M
authors.lastname: Eriksson
authors.forename: Olle
authors.initials: O
authors.lastname: Persson
mesh_terms: D019985:Benchmarking; D015706:Bibliometrics; D035843:Biomedical Research / Q000191:economics / Q000706:statistics & numerical data* / Q000639:trends; D017281:Cost of Illness; D003627:Data Interpretation, Statistical; D016206:Databases, Bibliographic; D016021:Epidemiologic Studies; D006801:Humans; D007391:International Cooperation; D007802:Language; D016012:Poisson Distribution; D011156:Population Density; D011634:Public Health; D012984:Software; D020521:Stroke / Q000453:epidemiology / Q000628:therapy; D013997:Time Factors