Time-course changes in clinical features of early-onset Japanese type 1 and type 2 diabetes: TWMU hospital-based study.

Using a database of patients with type 1 (n=1675) and type 2 (n=2259) diabetes diagnosed before the age of 30 years at the Diabetes Center, Tokyo Women's Medical University (TWMU), in which such Japanese patients have been registered at the time of first visit since the 1960s, we performed a hospital-based study over the last 40 years to clarify time-course changes in clinical features of type 1 and type 2 diabetes diagnosed before the age of 30 years. Type 2 diabetes had a male dominancy, while there has been a female dominancy in patients with type 1 diabetes as in previous reports of Japanese childhood-onset type 1 diabetes. Such dominances had been continued over the last 40 years. The number of patients with type 2 diabetes and with a past history of obesity increased with time. The age at which type 2 diabetes was diagnosed was suggested to have been getting lower with time, whereas that of type 1 diabetes has been higher with time. There was no marked difference in family history of diabetes in the first-degree relatives of patients with type 2 diabetes, regardless of the presence or absence of a past history of obesity. More female patients with type 2 diabetes diagnosed before the age of 15 years had mothers with type 2 diabetes compared to corresponding male patients.