The study aims to evaluate insulin as a potential biomarker for prediabetes in Singapore Chinese subjects.

The prevalence of type 2 diabetes (T2DM) in Singapore is expected to increase from 400,000 to 1,000,000 individuals by 2050, resulting in nearly US$2 billion in economic costs. Pre-diabetes is defined as an intermediate state of hyperglycemia where blood glucose levels are elevated but are below the diagnostic levels of diabetes. In Singapore, approximately 1 in 7, or 430,000 residents are estimated to be pre-diabetic, and globally this number is estimated at 7.3% of adults (equivalent to 352.1 million individuals). Up to 70% of pre-diabetics eventually develop overt T2DM; however, pre-diabetes may be reversible with early detection, providing a window for opportune disease interception.

While blood glucose is currently used to detect pre-diabetes, homeostatic mechanisms can maintain normal blood glucose levels and mask the detection of pre-diabetes until overt hyperglycemia is exhibited. In contrast, numerous studies have demonstrated that insulin levels increase markedly in pre-diabetes, even as marginal changes are observed in glucose levels. In this study, the investigator aims to determine if dynamic insulin levels observed during an oral glucose tolerance test are more sensitive than glucose alone in detecting prediabetes in a Singapore Chinese population.

Inclusion Criteria:

• Aged 21-60
• Chinese ethnicity
• Male or female
• Adequate fluency in the English language to understand the informed consent process, study instructions and study assessments.
• Sufficient vision and hearing to complete the study procedures
• Willing and able to participate and to give written informed consent

Exclusion Criteria:

• Diabetes diagnosis based on HbA1c ≥ 6.5%, and fasting plasma glucose ≥ 7.0 mmol/L
• Past (<3 months prior to the study) or current major metabolic, endocrine, gastrointestinal or cardiovascular disease
• Individuals diagnosed with non-alcoholic fatty liver disease
• Women diagnosed with polycystic ovary syndrome
• Major surgery in the past 2 months
• Past (<1 month prior to the study) or current use of prescription, over the counter or traditional medication that may influence metabolic or gastrointestinal functioning
• Presence or past history of alcohol or drug addiction
• Smoking
• Pregnant or lactating
• Alcohol intake >1 units per day
• Body Mass Index <18.5 kg/m2 or ≥30 kg/m2
• Member of the research team or their immediate family members