Abstract
The authors have reported diminished insulin response during OGTT in mothers of large babies and nondiabetic relatives of a juvenile diabetic patient. In the present study, one of a series on prediabetes, the insulin response to glucose in relatives of diabetic patients was evaluated using 4 indices established by the authors.
A total of 822 subjects who were admitted to the authors' institute for health check-ups, were studied. Of these subjects, 84 (10.2%) gave a family history of diabetes: 49 in first degree, 18 n second degree and 17 in third degree relatives. Among nonobese subjects, a diabetic type glucose tolerance test was found at a higher rate in relatives than in nonrelatives. Insulin secretion was definitely lower in the relatives, regardless the degree of glucose intolerance. Among obese subjects, however, no difference in rate of diabetic type glucose tolerance tests was found, although the ratio of those with glucose intolerance increased in the two groups as a whole.
In subjects with normal glucose tolerance, a marked decrease in the insulinogenic index and glucose-insulin coefficient was noted in nonobese relatives, suggesting decreased acute insulin secretion. The ratio of IRI area to glucose area was lower in relatives regardless obesity, indicating diminished total insulin secretion. The ratio of the IRI area during 30 min to the whole IRI area was also lower in nonobese relatives, and the insulin response was of a delayed type in this group.
It was concluded that both total and acute insulin secretion was diminished even in relatives of diabetic patients with normal glucose tolerance.
