Impaired early-phase insulin secretion is the major risk factor for glucose metabolism deterioration in the population with normal glucose tolerance / 中华内分泌代谢杂志

ABSTRACT

Objective To evaluate the effect of early-phase insulin secretion and insulin resistance in the pathogenesis of type 2 diabetes, and to analysis the risk factors of glucose tolerance deterioration. Methods Oral glucose tolerance test (OGTT) was performed in subjects over 30 years old coming from 78 families with type 2 diabetes. A total of 118 subjects with normal glucose tolerance (NGT) [fasting plasma glucose (FPG)<6.1 mmol/L and 2h postprandial glucose (2hPG)<7.8 mmol/L] were enrolled. Another OGTT was performed in them to define the glucose tolerance status at the end of the 4-7 years follow-up. AINS30/APG30, the ratio of the increment of insulin to that of plasma glucose at 30 min after the glucose load, was used to assess the early phase insulin secretion. HOMA-IR and HOMA-β were calculated to assess the insulin resistance and β-cell function respectively. Results After 4-7 years follow-up, 66 of 118 subjects still remained NGT, while 52 became either diabetic (n=11)or pre-diabetic (n=41). Using the median of HOMA-IR and AINS30/APG30 as the cutoff points, all subjects were divided into four groups subjects with good early phase insulin secretion and no insulin resistance, subjects with good early insulin secretion but relative insulin resistance, subjects with impaired early phase insulin secretion but no insulin resistance, subjects with impaired early phase insulin secretion and also relative insulin resistance. The incidences of abnormal glucose tolerance among these four groups were 23.1%, 36.4%, 45.5% and 73.1% respectively. There was a statistical difference between the former three groups and the last one (P<0.05). Log/st/c regression analysis showed that only the early phase insulin secretion was the risk factor of glucose tolerance deterioration, while age, gender, insulin resistance or β-cell function were not. Conclusion Impaired early phase insulin secretion is a major risk factor for the disturbance of glucose metabolism in the population with NGT.