Incidence of children with slowly progressive form of type 1 diabetes detected by the urine glucose screening at schools in the Tokyo Metropolitan Area

We investigated the incidence of the slowly progressive form of type 1 diabetes (SPT1D) detected by the urine glucose-screening tests at schools in the Tokyo Metropolitan Area from 1974 to 2004. During this study period, a total of 9,242,259 school students underwent the screening program. Of them, 54 children, 19 males and 35 females, aged 11.6 ± 2.4 years, were diagnosed to have SPT1D by this method. The overall incidence of SPT1D was 0.57/100,000/year, which was about one fifth of that of type 2 diabetes detected by the same method. The incidence was significantly higher in junior high school students than in primary school students (0.32 vs. 1.13/100,000/year, p < 0.0001). SPT1D accounts for one third of all pediatric cases of type 1 diabetes in Japan, showing that this clinical form is not rare in Japan. There were no significant changes in the incidence of SPT1D during the study period. The incidence of type 1 diabetes in Japanese children is quite low in comparison with Caucasian populations. This incidence, regardless of the clinical form of the disease, does not seem to be influenced by environmental factors in contrast with that of type 2 diabetes.