Figure 2. Total fertility rate (TFR), incidence, and mean age of Kawasaki disease, 1979–2010.

Prefectures were classified based upon annual incidence (/100,000 children between 0 and 4 years) (a), crude mean patient age (years) (b), and TFR (c). TFR was also presented in reverse order (d). The similarity between (a) and (d), and that between (b) and (d) implied negative correlations between incidence and TFR, and between mean patient age and TFR, respectively. The cut-off values were selected by natural breaks classification algorithm. Only the main islands are presented.