Impaired glucose tolerance

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Impaired glucose tolerance
Specialty Endocrinology Edit this on Wikidata

Impaired glucose tolerance (IGT) is a pre-diabetic state of hyperglycemia that is associated with insulin resistance and increased risk of cardiovascular pathology. IGT may precede type 2 diabetes mellitus by many years. IGT is also a risk factor for mortality.[1]


According to the criteria of the World Health Organization and the American Diabetes Association, impaired glucose tolerance is defined as:[2][3][4]

  • two-hour glucose levels of 140 to 199 mg per dL (7.8 to 11.0 mmol/l) on the 75-g oral glucose tolerance test. A patient is said to be under the condition of IGT when he/she has an intermediately raised glucose level after 2 hours, but less than the level that would qualify for type 2 diabetes mellitus. The fasting glucose may be either normal or mildly elevated.

From 10 to 15 percent of adults in the United States have impaired glucose tolerance or impaired fasting glucose.[5]


The risk of progression to diabetes and development of cardiovascular disease is greater than for impaired fasting glucose.[6]

Although some drugs can delay the onset of diabetes, lifestyle modifications play a greater role in the prevention of diabetes.[5][7] Patients identified as having an IGT may be able to prevent diabetes through a combination of increased exercise and reduction of body weight.[5] "Drug therapy can be considered when aggressive lifestyle interventions are unsuccessful."[5]

See also[edit]


  1. ^ Barr EL, Zimmet PZ, Welborn TA, et al. (2007). "Risk of cardiovascular and all-cause mortality in individuals with diabetes mellitus, impaired fasting glucose, and impaired glucose tolerance: the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab)". Circulation. 116 (2): 151–57. doi:10.1161/CIRCULATIONAHA.106.685628. PMID 17576864. 
  2. ^ .World Health Organization. "Definition, diagnosis and classification of diabetes mellitus and its complications: Report of a WHO Consultation. Part 1. Diagnosis and classification of diabetes mellitus". Retrieved 2007-05-29. 
  3. ^ American Diabetes, Association (2005). "Diagnosis and classification of diabetes mellitus". Diabetes Care. 28 Suppl 1: S37–42. doi:10.2337/diacare.28.suppl_1.s37. PMID 15618111. 
  4. ^ "Impaired Glucose Tolerance (IGT)". Retrieved 17 April 2018. 
  5. ^ a b c d Shobha S. Rao; Phillip Disraeli; Tamara McGregor (15 April 2004). "Impaired Glucose Tolerance and Impaired Fasting Glucose". American Family Physician. 69 (8): 1961. 
  6. ^ Oxford Handbook of Clinical Medicine, 7th Ed., Longmore, Wilkinson, Turmezei and Cheung. Oxford University Press 2007.
  7. ^ Raina Elley C, Kenealy T (December 2008). "Lifestyle interventions reduced the long-term risk of diabetes in adults with impaired glucose tolerance". Evid Based Med. 13 (6): 173. doi:10.1136/ebm.13.6.173. PMID 19043031. 

Further reading[edit]

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