title: Corneal confocal microscopy detects neuropathy in subjects with impaired glucose tolerance.
abstract: OBJECTIVE
  Impaired glucose tolerance (IGT) represents one of the earliest stages of glucose dysregulation and is associated with macrovascular disease, retinopathy, and microalbuminuria, but whether IGT causes neuropathy is unclear.
  
  
  METHODS
  Thirty-seven subjects with IGT and 20 age-matched control subjects underwent a comprehensive evaluation of neuropathy by assessing symptoms, neurological deficits, nerve conduction studies, quantitative sensory testing, heart rate variability deep breathing (HRVdb), skin biopsy, and corneal confocal microscopy (CCM).
  
  
  RESULTS
  Subjects with IGT had a significantly increased neuropathy symptom profile (P < 0.001), McGill pain index (P < 0.001), neuropathy disability score (P = 0.001), vibration perception threshold (P = 0.002), warm threshold (P = 0.006), and cool threshold (P = 0.03), with a reduction in intraepidermal nerve fiber density (P = 0.03), corneal nerve fiber density (P < 0.001), corneal nerve branch density (P = 0.002), and corneal nerve fiber length (P = 0.05). No significant difference was found in sensory and motor nerve amplitude and conduction velocity or HRVdb.
  
  
  CONCLUSIONS
  Subjects with IGT have evidence of neuropathy, particularly small-fiber damage, which can be detected using skin biopsy and CCM.
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Omar
authors: O
authors: Asghar
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Ioannis N
authors: IN
authors: Petropoulos
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Uazman
authors: U
authors: Alam
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Wendy
authors: W
authors: Jones
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Maria
authors: M
authors: Jeziorska
authors: Department of Clinical Neurophysiology, Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Andrew
authors: A
authors: Marshall
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Georgios
authors: G
authors: Ponirakis
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Hassan
authors: H
authors: Fadavi
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Andrew J M
authors: AJ
authors: Boulton
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors: Mitra
authors: M
authors: Tavakoli
authors: Institute of Human Development, Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K. Weill Cornell Medical College in Qatar, Doha, Qatar rayaz.a.malik@manchester.ac.uk.
authors: Rayaz A
authors: RA
authors: Malik
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003315:Cornea / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism; D018149:Glucose Intolerance / Q000150:complications* / Q000473:pathology; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009460:Neurologic Examination; D010147:Pain Measurement; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology
chemical_list: D005947:Glucose