Impaired Glucose Tolerance (IGT) is a state when the person has blood glucose levels that are higher than normal, but below the level of diabetes. It is a pre-diabetic state of Dysglycemia. Impaired Glucose Tolerance occurs when there is impaired secretion of insulin or a reduction in insulin sensitivity (insulin resistance) in the body. Impaired Glucose Tolerance can easily lead to Type II Diabetes. According to the U.S. Department of Health and Human Services approximately 1-in-4 Americans over the age of 20 has pre-diabetes.

Some facts about IGT have been listed below:

  • Approximately 40-50% of patients suffering from Impaired Glucose Tolerance are likely to develop Type II Diabetes.
  • Approximately 30% of patients suffering from Impaired Glucose Tolerance may regain normal glucose tolerance.
  • Patients of impaired glucose tolerance have a higher risk of developing cardiovascular disease and micro-vascular complications within 10 years.
  • Cardiovascular complications associated with Type II Diabetes may start well before a diagnosis of Type II Diabetes. The complications can start in a pre-diabetes state and macro-vascular damage may already be well advanced, by the time Type II Diabetes is diagnosed.
  • In 2003, there were 314 million people – comprising 8.2% of the adult population  – were diagnosed with impaired glucose tolerance.
  • There are estimates that number of people suffering from impaired glucose tolerance may increase to 472 million comprising 9.0% of the adult population by 2025.
  • The South-East Asia Region boasts of highest number of people suffering from Impaired Glucose Tolerance. The number of IGT patient in this region is 93 million, which comprises 13.2% of the adult population.
  • The Western Pacific Region is the second as far as number of patients of impaired glucose tolerance is concerned. It has approximately 78 million people suffering from IGT. But this region has lowest prevalence rate of 5.7%.
  • It is estimated that the South-East Asian Region will secure its position by having the highest prevalence rate with 13.5% by 2025.
  • It is estimated that by 2025 European Region will have second highest prevalence rate of IGT by having prevalence rate of 10.9%.
  • African and South-East Asian Regions show a prevalence rate of IGT double than prevalence rate of Diabetes.
  • In the Eastern Mediterranean and the Middle East, and the North American Regions have little difference between prevalence of IGT and Diabetes. It has prevalence of IGT slightly lower than that of diabetes.
  • The third National Health and Nutrition Examination Survey (NHANES) carried out in 1988-1994 have found out that the prevalence of IGT increased with age.
  • The third National Health and Nutrition Examination Survey (NHANES) carried out in 1988-1994 also concluded that there was no significant difference between men and women.
  • The third National Health and Nutrition Examination Survey (NHANES) carried out in 1988-1994 also found out that certain ethnic groups such as Mexican Americans, African Americans and Native Americans had a higher prevalence of IGT.
  • The third National Health and Nutrition Examination Survey (NHANES) carried out in 1988-1994 also concluded that the prevalence of IGT in Europe was similar to that in theUSA
  • The DECODE (Diabetes Epidemiology: Collaborative analysis Of Diagnostic criteria in Europe) study revealed that raised blood glucose two hours after consuming 75g glucose is can increase risk for premature death.
  • The DECODE (Diabetes Epidemiology: Collaborative analysis Of Diagnostic criteria in Europe) study concluded that patients of IGT are at 50% higher risk of death due to cardiovascular complications during follow-up than people with normal blood glucose control.
  • The loss of early insulin secretion in the state of impaired glucose tolerance is caused due to malfunctioning of the pancreatic ß-cells.  It further deteriorates ß-cell function and worsens blood glucose control.
  • Increased his physical activity, maintaining a healthy weight and healthy balanced diet are helpful in preventing IGT.
  • Impaired glucose tolerance or pre-diabetes is diagnosed by two different blood tests. First one is fasting plasma glucose (FPG) test and the second one is oral glucose tolerance test (OGTT).