Annual Incidence and Clinical Characteristics of Type 2 Diabetes in Children as Detected by Urine Glucose Screening in the Tokyo Metropolitan Area

Abstract

OBJECTIVE—This study investigates the annual incidence and clinical characteristics of type 2 diabetes among school-aged children as detected by urine glucose screening from 1974 to 2002 in the Tokyo metropolitan area. RESEARCH DESIGN AND METHODS— In total, 8,812,356 school children were examined for glucosuria. Morning urine was used for the analysis. When the urine was positive for glucose, an oral glucose tolerance test was carried out to confirm diabetes. RESULTS—In all, 232 students were identified to have type 2 diabetes. The overall annual incidence of type 2 diabetes was 2.63/100,000. The annual incidence after 1981 was significantly higher than that before 1980 (1.73 vs. 2.76/100,000, P < 0.0001). The annual incidence was significantly higher for junior high school students compared with primary school students (0.78 vs. 6.43/100,000, P < 0.0001). The overall male-to-female ratio of students with type 2 diabetes was 1.0:1.19 (P = 0.296), but it was 1.0:1.56 (P = 0.278) for primary school students. Overall, 83.4% of children with diabetes were obese (≥20% overweight). However, nonobese girls (<20% overweight) with diabetes accounted for 23.0% of the patients, whereas markedly obese boys (≥40% overweight) accounted for 61.5% of the patients. The frequency of a family history of type 2 diabetes in second- and first-degree relatives was 56.5%. CONCLUSIONS—We confirmed that the incidence of young people with type 2 diabetes increased after 1981 in the Tokyo metropolitan area. The increase in the frequency of this disorder seemed to be strongly related to an increasing prevalence of obesity. Age and genetic susceptibility may be associated with the occurrence of type 2 diabetes.