About Fasting Blood Glucose
Fasting glucose is the amount of sugar in the blood after eight hours or more without eating. There are two methods for testing fasting blood glucose: the fasting plasma glucose test and the oral glucose tolerance test. The fasting plasma glucose test measures the blood after eight hours of fasting and a result greater than 126 is considered high. The oral glucose tolerance test requires the patient fast for eight hours then drink a glucose solution and wait two hours–a result greater than 200 is considered high. Diabetes is the most common cause of high fasting blood glucose but, other endocrine and metabolic disorders and medications can also cause high fasting blood glucose.
Diabetes is a condition where the body is unable to adequately process glucose. There are two major types of diabetes: type 1, type 2 and a third form known as gestational diabetes. Type 1 diabetes is also known as insulin-dependent and occurs when the pancreas stops producing insulin. Type 1 diabetes occurs most often in children. Type 2 diabetes is also known as late-onset and occurs when the pancreas produces insulin but the body does not use it properly. Type 2 is most common in people over 40 and is linked to lifestyle, body weight and physical activity. Type 2 diabetes does have a hereditary component and Hispanics, Asians and African Americans are at greater risk. The is also considered preventable with simple dietary, exercise and lifestyle changes. Gestational diabetes only affects pregnant women and is similar to type 2 in that the pancreas makes insulin but the body does not respond to it. Gestational diabetes may go away once the woman gives birth but she may be at greater risk for developing it in future pregnancies and for developing type 2 diabetes later in life.
Cushing’s syndrome, an adrenal disorder, and damage to the pituitary gland can both affect blood glucose levels. The pituitary gland controls most of the other glands in the body, including the pancreas and the adrenal glands. The pancreas also plays two roles in managing blood sugar: it releases glucagon, which stimulates the liver to release glucose into the blood stream, and it releases insulin to help the body metabolize blood sugar. When the body responds to stress, the adrenal system releases cortisol, which stimulates the pancreas to release glucagon. Cushing’s syndrome causes the adrenal glands to release too much cortisol, which can cause a momentary spike in blood sugar levels. Damage or disease to the pituitary gland can also cause the pancreas or adrenals to malfunction, resulting in impaired blood sugar levels.
Medications like Zyprexa have been known to cause an increase in blood sugar. A patient taking Zyprexa for an extended period may experience high fasting blood sugar levels.