RESUMEN
Background: Recently launched, the system for granting a medical specialty in Japan raised has concerns about exacerbating the regional maldistribution of medical doctors. The aim of this study is to clarify the characteristics of prefectures that are gathering larger numbers of trainees under this system. Methods: We performed a factor analysis of population structure, medical care and the number of trainees in the system and studied the correlations between the number of trainees and related items. Results: The factor analysis extracted two principal components using Varimax rotation (cumulative ratio of the total variance: 70%). The first principal component suggested an aging society, and the second suggested educational conditions. According to the analysis, the number of trainees was closely related to the educational conditions (1st principal component: -0.19, second principal component: 0.96). In the correlation analysis, the number of trainees closely correlated with the number of doctors in medical school (r=0.80, P<0.001), although it was weakly correlated with urbanization rate (r=0.32, P=0.03). Discussion: This study revealed that the prefectures that are gathering a large number of the trainees are characterized as having a sufficient number of teaching doctors. The trainees might be choosing specific training hospitals to receive relevant specialty training.