The study cohort had 1234 unrelated T2D patients and 606 controls. All participants gave written informed consent at the time of blood sampling. Ethics approval was obtained from the Clinical Research Ethics Committee of Chinese University of Hong Kong, Shatin, NT, Hong Kong. All T2D participants were selected from the Hong Kong Diabetes Registry. Control participants were recruited in a community health screening program for cardiovascular risk factors and some were hospital staff (3.1%, n = 19). No subdemographic differences were detected in control participants. All control participants had no known history of diabetes and had fasting plasma glucose (FPG) , 6.1 mmol/l. Clinical assessments of participants had been described elsewhere [11] . Body mass index (BMI), blood pressure (BP) as well as fasting blood biochemical and metabolic profiles were measured. Among the 1234 T2D patients, 9.8% (n = 121) were on diet treatment only, 41.3% (n = 510) were on oral anti-diabetic drugs only, 12.5% (n = 154) were on insulin only, 9.5% (n = 117) on both oral anti-diabetic drugs and insulin, and 7.3% (n = 90) were treated for dyslipidemia.