Insulin and glucose

Insulin, produced by the pancreas, is the substance which allows the body to make use of sugar. Insulin resistance suggests that the body is not responding properly to insulin. A consequence of insulin resistance is a rise in both insulin and sugar levels in the blood. Insulin resistance and high blood levels of insulin and glucose are associated with lipodystrophy.

Glucose tolerance is measured either by checking fasting glucose levels or by a two-hour glucose tolerance test, which checks how high blood glucose levels have risen after two hours in response to the infusion of a set amount of glucose.

Fasting glucose levels between 6.1 and 6.9 mm are called impaired glucose tolerance if two-hour glucose tolerance lies between 7 and 11 mm. Fasting glucose levels above 7mm and two-hour glucose tolerance above 11.1mm are called diabetes.

To convert glucose measurements from mm to mg/dl, multiply by 18. To convert glucose measurements from mg/dl to mm, multiply by 0.0555.

If you are diagnosed with impaired glucose tolerance or diabetes, various interventions will be recommended in order to restore normal glucose tolerance (or to prevent the condition from getting worse):

• Switching from a PI- to a non-PI-containing regimen if it is your first regimen.
• Increasing exercise levels. Exercise improves glucose tolerance.
• Dietary changes as recommended by a dietitian.
• Aim to reduce body mass index (BMI) below 25 by a combination of diet and exercise. BMI is calculated by dividing your weight by the square of your height (in metric measures).
• Treatment with metformin to restore a more normal response to insulin, if you do not have severe fat wasting and your BMI is above 25 (high body fat).
• In people with intermediate body fat (BMI 18 to 25), sulphonylurea treatment may be recommended.
• If you have severe fat wasting (BMI below 18), rosiglitazone may be recommended instead, because metformin may further increase fat loss, whereas drugs of the glitazone class may encourage the accumulation of some subcutaneous fat. A US meta-analysis has suggested that rosiglitazone may increase the risk of death from heart attack; this analysis has been disputed and has not yet been acted upon by the US Food and Drug Administration. (Also see Treating fat loss - other treatment approaches for a further discussion of rosiglitazone and metabolic disorders.)