Impaired glucose tolerance (also known as pre-diabetes) is a condition characterized by the slight elevation of the blood glucose levels.
Impaired glucose tolerance is a condition when blood glucose is slightly elevated but it is not as high as in case of diabetes. Those who have impaired glucose tolerance are at risk of developing type 2 diabetes mellitus within 10 years, therefore, this condition is also referred to as pre-diabetes. Additionally, raised levels of glucose are associated with increased risk of the cardiovascular and cerebrovascular diseases, including arterial hypertension (high blood pressure), stroke and myocardial infarction.
This disorder usually doesn’t cause any symptoms and may be an accidental finding so most of the affected individuals do not know about their condition, although it is important to spot the abnormality as soon as possible in order to prevent the development of diabetes. Our test may be used to measure your blood glucose level, whereas genetic testing will be helpful to determine whether you are at risk of developing diabetes mellitus.
Causes and risk factors
Impaired glucose tolerance is caused by the decreased cells’ sensitivity to insulin (hormone produced by the pancreas which is necessary for the penetration of the glucose through the cells’ membranes), which develops over time in individuals with genetic predisposition and unhealthy diet. Therefore, the level of blood glucose rises gradually and exceeds the normal values, although doesn’t reach the values characteristic of diabetes. Nevertheless, if a person doesn’t change his lifestyle eventually he will develop type 2 diabetes.
Risk factors for pre-diabetes are similar to those leading diabetes mellitus type 2 including:
- Abdominal obesity and overweight with body mass index greater than 25 kg/m2;
- Sedentary lifestyle and lack of physical activity;
- Family history of diabetes;
- Gestational diabetes (women develop diabetes during pregnancy) or giving birth to a large baby;
Impaired glucose tolerance: Oral glucose tolerance test
Oral glucose tolerance test is performed to check the body’s reaction to sugar consumption and its ability to absorb glucose. At first the fasting glucose levels are measured. Afterwards a person is asked to drink a solution which contains 75 grams of sugar and the blood samples are taken one and two hours later.
According to the results of this test either diabetes, gestational diabetes or impaired glucose tolerance may be diagnosed.
Impaired glucose tolerance: Criteria
Pre-diabetes is diagnosed when a fasting blood glucose is of less than 7 mmol/l, whereas two hours after oral glucose tolerance test blood glucose is higher than 7.8 mmol/l, but less than 11.1 mmol/l.
Impaired fasting glycemia
There is also another condition somewhat opposite to impaired glucose tolerance. This condition, known as impaired fasting glycemia when a fasting glucose is high with a glucose level of 6.1 to 6.9 mmol/l, whereas after an oral glucose tolerance test a blood glucose is less than 7.8 mmol/l.
Impaired fasting glycemia (blood glucose) is also associated with an increased risk of developing diabetes, although individuals with this disorder are less likely to develop diabetes than those who have impaired glucose tolerance.
Management and diabetes prevention
The disorder requires lifestyle changes and administration of some drugs.
- Diet and weight loss are helpful to postpone the development of diabetes;
- Being physically active also provides benefit for the body’s glucose metabolism and
- Drugs like metformin or acarbose may be prescribed for such patients and were shown to effectively reduce the risk of transition to diabetes.