Patterns of co-authorship in international epidemiology

Background: The objective of this study was to identify current patterns of international collaboration based on authorship of epidemiological articles. Methods: All articles published in nine high-impact public health journals in 2006 were read, and information about the study country and the authors' countries of affiliation was extracted. All countries were assigned to an income level using World Bank classifications. This paper presents results for the 1686 articles that focused on a single study country. Results: International collaboration is common, but the dominant partnerships vary by the income level of the study country. 74.2% of articles reporting on research conducted in low-and middle-income study countries involved co-authors from two or more countries, and nearly all of these international collaborations included coauthors from both low/middle-income and high-income countries. Only 13.0% of studies based in high-income countries involved co-authors from two or more countries, and the majority of these studies involved co-authors with affiliations solely from high-income countries. More than 90% of articles from both low/middle- and high-income study countries included at least one co-author from the study country. Conclusion: There is a high rate of local co-authorship in both low/middle- and high-income study countries. Most articles that focus on high-income countries include only authors from high-income countries. Most articles that focus on low-and middle-income study countries are "north-to-south'' international collaborations that include co-authors from both low/middle- and high-income countries. "South-south'' partnerships are rare.