Objective:To calculate prevalence of insulin resistance(IR) among individuals who met the criteria for Metabolic Syndrome(MS) of International Diabetes Federation(IDF) definition and to investigate clinical characteristics and β-cell function in patients of MS with or without IR.Methods:Random stratified sampling method was applied to the cross-sectional epidemiology survey on subjects aged 20years and over in Chongqing district.For all subjects

somatometry parameters were tested

75gram oral glucose tolerance tests were conducted

and some other parameters were also detected

like blood glucose

lipid-profile and insulin.Data of 2323 subjects with complete laboratory data were gathered for analysis.Homeostasis model assessment of insulin resistance(Homa-IR) was used to estimate insulin resistance

and Homa-β and disposition index(DI) to evaluate β-cell function.Results:(1)MS was presented in 482 individuals(20.77%)

diagnosed according to the definition proposed by IDF in 2005.In those subjects with MS

there were 290 individuals(60.17%) with IR and 192 individuals(39.83%) without IR.(2)The MS without IR group had lower body mass index

fasting and 2h post-load plasma glucose

diastolic blood pressure and triglyceride than the MS with IR group

and the difference was significant(P<0.05).(3)Compared with control subjects(98.60±56.18)

DI of MS with and without IR groups both significantly decreased(respectively 39.69±29.35 and 57.49±30.62)

and the differences between every two of them were significant(P<0.01).(4)DI of control subjects

normal glucose tolerance subjects of MS without IR group(66.49±30.06) and hyperglycemic patients of MS without IR group(45.14±26.98)decreased in order

and the differences between every two of them were also significant(P<0.01).Conclusion:Not all individuals with MS presented IR.The state of metabolic disturbance was less serious in subjects of MS without IR.No matter with or without IR

the patients of MS presented impaired β-cell function.