Trends in the core literature on tropical medicine: A bibliometric analysis from 1952-2002

The medical specialty of tropical medicine only dates back a little more than 100 years and, in the meantime, has gone through several quite distinctive eras. The aim of our study was to investigate trends that occurred in the leading literature on tropical medicine over the past 50 years. We analysed 2,802 original articles published in 1952, 1962, 1972, 1982, 1992 and 2002 in five of the high impact factor journals, namely (i) Acta Tropica, (ii) American Journal of Tropical Medicine and Hygiene, (iii) Annals of Tropical Medicine and Parasitology, (iv) Leprosy Review, and (v) Transactions of the Royal Society of Tropical Medicine and Hygiene. Authors' country affiliations were categorized according to the human development index 2003 (HDI), with stratification into low, medium and high HDI. We observed the following trends: First, there was a strong increase in the number of articles published from 250 in 1952 to 726 in 2002. Second, over the same time span, the median number of authors per article increased from I (four journals) or 2 (American Journal of Tropical Medicine and Hygiene) to 2.5 (Leprosy Review) up to 6 (Acta Tropica and American Journal of Tropical Medicine and Hygiene). Third, research collaborations between countries of different HDI ranks increased concomitantly - in 2002, 19.4-43.7% of all manuscripts comprised authors from different HDI countries - indicating that tropical medicine has become a global endeavour. However, in four of the five journals investigated, the overall percentage of researchers affiliated with low HDI countries decreased over the past 50 years and only a slight positive trend can be observed over the last decade. Concluding, current roadblocks should be identified and programmes designed and implemented to enhance equity of publishing in tropical medicine. This in cum might be an important step forward to substantially reduce the current burden of tropical diseases, so that social and economic development in the tropics and subtropics can be advanced and poverty alleviated.