Japan's contribution to clinical pediatrics research in the last decade

Objective: To determine Japan's contribution to research in clinical pediatrics over the last decade. Methods: Articles published in highly reputable pediatrics journals from 1991-2000 were accessed through the MEDLINE database. The number of articles which had an affiliation with a Japanese institution were counted for each of the journals and also summed in total. Proportions of randomized controlled trials (RCTs) and case-control/cohort studies among the articles from Japan were also generated and compared with the average for the entirety. In addition, shares of the top-ranking countries were presented along with their trend over time. Results: In total, 20 189 articles were published in the selected seven pediatric journals from 1991-2000. Japan contributed 3.0% of these articles and this contribution was ranked 7th in the world. A negative trend was noticed in Japan's contribution over time but it was not statistically significant (z = -0.40, P = 0.16). RCTs accounted for 7. 3% of the total articles, but only 0.34% of those from Japan. Conclusions: Japan's share of articles in pediatrics research was smaller than that in basic science and some of the other clinical fields. The number of articles from Japan providing a high level of evidence was meager in this field.