Fasting Blood Glucose and HbA1c Measurement

Data about demographic and laboratory features were collected from hospital records or by questionnaire. The blood samples were withdrawn from the antecubital vein of subjects in fasting status, and the level of fasting blood glucose of each individual was detected by hexokinase method by Roche cobase 702. Cases having serum level of fasting blood glucose between 2.2 and 6.1 mmol/L were considered as normality, while serum level of fasting blood glucose <2.2 or >6.1 mmol/L were considered as abnormality.^{[13 (link)–15 (link)]} In addition, the level of glycosylated hemoglobin a1c (HbA1c) was detected by high performance liquid chromatography (HLC-723G7; Tosoh, Tokyo, Japan), which was certified by the National Glycohemoglobin Standardization Program.^{[16 (link)]} The level of HbA1c higher than 6.5% was considered abnormality.^{[17 (link)]}