Abstract
We examined Japanese diabetic patients with diagnosis before the age of 30 and evaluated their cases to ditermine if a time-trend for the calendar year existed in the following categories: onset age of diabetes, type of diabetes and gender difference. Between 1980 and 1995, 2, 176 Japanese patients were registered in our Diabetes Center with onset of diabetes before the age of 30. Of these 2, 176 patient, 841 (39%) had insulin-dependent diabetes mellitus (IDDM), and 1, 335 (61%) had non-insulin-dependent diabetes mellitus (NIDDM). The time-trend regarding these categories was investigated by assigning patients to the following groups: group A, diagnois between 1960 and 1975, group B, diagnosis between 1976 and 1985, and group C, diagnosis between 1986 and 1995. NIDDM patients with a diagnosis before the age of 9 were present in all three groups. The numbers of both male and female IDDM patients with onset after 20 years of age, were increased in group C, but not in groups A and B (p<0.0001). Regarding NIDDM, the number of male patients with a diagnosis between the ages of 14 and 17 years was more increased in groups A and C than that in group A (A vs B; p<0.0001, A vs C; p<0.0001). The number of female NIDDM patients showed a similar finding in all three groups as in male NIDDM patients.
