Objective:To investigate insulin resistance(IR) and islet β-cell function in nondiabetic first-degree relatives(FDR) of patients in type 2 diabetes(T2DM) families.Methods:195 FDR with impaired glucose regulation(FIGR group)

232 FDR with normal glucose tolerance(FNGT group) and 161 NGT spouses of probands or siblings(NC group)

which come from 251 T2DM families including at least two T2DM patients in Chongqing district

were selected.The subjects of FIGR group were divided into 3 groups: isolated impaired fasting glucose(iIFG)

isolated impaired glucose tolerance(iIGT) and combined IFG and IGT(IFG/IGT).For all subjects

75 gram oral glucose tolerance tests were conducted.Blood glucose

lipid-profile and insulin were assayed.Homeostasis model assessment of insulin resistance(Homa-IR) was used to estimate insulin resistance

and disposition index(DI) was used to evaluate islet β-cell function(DI1=Homa-β/ Homa-IR

DI2=△I30/△G30/ Homa-IR).Results:(1)After adjustment of age

sex and body mass index(BMI)

compared with NC group

systolic blood pressure and Homa-IR increased and DI1 decreased in FNGT group and the difference was significant(P﹤0.05).Systolic blood pressure

triglyceride

plasma glucose and serum insulin levels during OGTT and Homa-IR of FIGR group were higher than those of NC group;while Homa-β

△I30/△G30

DI1 and DI2 of FIGR group were lower

and the difference was significant(P﹤0.01).(2)iIGT and IFG/IGT had higher plasma glucose at 60min and 120min

serum insulin at 120min during OGTT compared with iIFG(P﹤0.01)

and the difference was significant.Compared with iIGT

Homa-IR increased and Homa-β

DI1 decreased in iIFG and IFG/IGT

and the difference was significant(P﹤0.05).DI2 of iIFG

iIGT and IFG/IGT decreased in turn.DI2 of IFG/IGT was much lower than that of the two formers

and the difference was significant(P﹤0.01).Conclusion:Non-diabetic FDR of T2DM patients presented IR and disfunction of β-cell.