Can Vitamin D Supplementation Prevent Type 2 Diabetes?

The clamp will be used to measure insulin sensitivity. The clamp is initiated by an intravenous bolus injection of insulin (9milliUnit/kg). Insulin is then constantly infused at a rate of 40 milliUnit.m-2.min-1 for 120 min into an arm vein, whilst glucose is variably infused to maintain euglycaemia. Plasma glucose values will be monitored every 5 minutes during the clamp and the variable infusion rate of glucose is adjusted to maintain blood glucose at a constant value of 5mmol/L.

The clamp will be used to measure insulin sensitivity. The clamp is initiated by an intravenous bolus injection of insulin (9milliUnit/kg). Insulin is then constantly infused at a rate of 40 milliUnit.m-2.min-1 for 120 min into an arm vein, whilst glucose is variably infused to maintain euglycaemia. Plasma glucose values will be monitored every 5 minutes during the clamp and the variable infusion rate of glucose is adjusted to maintain blood glucose at a constant value of 5mmol/L.

Plasma inflammatory markers (interleukin 1β, 6, 8 and 10, TNFα, macrophage migration inhibitory factor, monocyte chemotactic protein-1) will be measured by quantitative sandwich enzyme immunoassays (R & D Systems Inc, USA) (interassay Coefficients of Variation: 7.2%, 10.2%, 5.8%, respectively). Plasma C- reactive protein (hsCRP) via a high sensitivity assay (BN-II nephelometer; Dade Behring Diagnostics, NSW).

Plasma inflammatory markers (interleukin 1β, 6, 8 and 10, TNFα, macrophage migration inhibitory factor, monocyte chemotactic protein-1) will be measured by quantitative sandwich enzyme immunoassays (R & D Systems Inc, USA) (interassay Coefficients of Variation: 7.2%, 10.2%, 5.8%, respectively). Plasma C- reactive protein (hsCRP) via a high sensitivity assay (BN-II nephelometer; Dade Behring Diagnostics, NSW).

body composition by dual energy x-ray absorptiometry (DEXA), which is a non-invasive assessment of soft tissue composition by region with a precision of 4-5%; central adiposity assessed in duplicate using a constant-tension tape for taking waist, and hip circumference. Bioimpedance measurement will be also collected for validation purposes.

body composition by dual energy x-ray absorptiometry (DEXA), which is a non-invasive assessment of soft tissue composition by region with a precision of 4-5%; central adiposity assessed in duplicate using a constant-tension tape for taking waist, and hip circumference. Bioimpedance measurement will be also collected for validation purposes.

After a 10-12 h overnight fast, participants will ingest 75g of glucose over 2 mins. Blood samples will be drawn at 0, 30, 60, 90 and 120 min for plasma glucose and insulin concentrations. We will evaluate the area under the curve.

After a 10-12 h overnight fast, participants will ingest 75g of glucose over 2 mins. Blood samples will be drawn at 0, 30, 60, 90 and 120 min for plasma glucose and insulin concentrations. We will evaluate the area under the curve.

This will be measured in response to 25g intravenous glucose and calculated as the average incremental plasma insulin level from the third to the fifth minute after the glucose bolus.

This will be measured in response to 25g intravenous glucose and calculated as the average incremental plasma insulin level from the third to the fifth minute after the glucose bolus.

We will measure changes in the expression and activation of important insulin signalling proteins, including the insulin receptor,and we will measure inflammation markers in skeletal, muscle and adipose tissue.

We will measure changes in the expression and activation of important insulin signalling proteins, including the insulin receptor,and we will measure inflammation markers in skeletal, muscle and adipose tissue.

Resting systolic and diastolic blood pressure and pulse rate will be measured using an automated oscillometric measurement system (Dinamap, USA) after a 30 minute rest.

Resting systolic and diastolic blood pressure and pulse rate will be measured using an automated oscillometric measurement system (Dinamap, USA) after a 30 minute rest.

This is done with the BP+ device (Uscom, Australia). This is a device for non-invasive measurement of central blood pressure and augmentation index using an oscillometric method.

This is done with the BP+ device (Uscom, Australia). This is a device for non-invasive measurement of central blood pressure and augmentation index using an oscillometric method.

The Beck Depression Inventory (BDI), created by Dr. Aaron T. Beck, is a 21-question multiple-choice self-report inventory, one of the most widely used instruments for measuring the severity of depression. It is designed for individuals aged 13 and over, and is composed of items relating to symptoms of depression such as hopelessness and irritability, cognitions such as guilt or feelings of being punished, as well as physical symptoms such as fatigue, weight loss, and lack of interest in sex.

The Beck Depression Inventory (BDI), created by Dr. Aaron T. Beck, is a 21-question multiple-choice self-report inventory, one of the most widely used instruments for measuring the severity of depression. It is designed for individuals aged 13 and over, and is composed of items relating to symptoms of depression such as hopelessness and irritability, cognitions such as guilt or feelings of being punished, as well as physical symptoms such as fatigue, weight loss, and lack of interest in sex.

PIQ-6 measures the severity of pain and its impact on work and leisure activities, as well as on emotional well-being within a variety of diseases and general populations. This survey is intended for adults 18 years of age and older.

PIQ-6 measures the severity of pain and its impact on work and leisure activities, as well as on emotional well-being within a variety of diseases and general populations. This survey is intended for adults 18 years of age and older.