title: Early neurodegeneration in the retina of type 2 diabetic patients.
abstract: OBJECTIVE
  The purpose of this study was to determine whether diabetes type 2 causes thinning of retinal layers as a sign of neurodegeneration and to investigate the possible relationship between this thinning and duration of diabetes mellitus, diabetic retinopathy (DR) status, age, sex, and glycemic control (HbA1c).
  
  
  METHODS
  Mean layer thickness was calculated for retinal layers following automated segmentation of spectral domain optical coherence tomography images of diabetic patients with no or minimal DR and compared with controls. To determine the relationship between layer thickness and diabetes duration, DR status, age, sex, and HbA1c, a multiple linear regression analysis was used.
  
  
  RESULTS
  In the pericentral area of the macula, the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) were thinner in patients with minimal DR compared to controls (respective difference 1.9 μm, 95% confidence interval [CI] 0.3-3.5 μm; 5.2 μm, 95% CI 1.0-9.3 μm; 4.5 μm, 95% CI 2.2-6.7 μm). In the peripheral area of the macula, the RNFL and IPL were thinner in patients with minimal DR compared to controls (respective difference 3.2 μm, 95% CI 0.1-6.4 μm; 3.3 μm, 95% CI 1.2-5.4 μm). Multiple linear regression analysis showed DR status to be the only significant explanatory variable (R = 0.31, P = 0.03) for this retinal thinning.
  
  
  CONCLUSIONS
  This study demonstrated thinner inner retinal layers in the macula of type 2 diabetic patients with minimal DR than in controls. These results support the concept that early DR includes a neurodegenerative component.
authors.affiliation: Department of Ophthalmology, Academic Medical Center, Amsterdam, The Netherlands. h.w.vandijk@amc.nl
authors.forename: Hille W
authors.initials: HW
authors.lastname: van Dijk
authors.forename: Frank D
authors.initials: FD
authors.lastname: Verbraak
authors.forename: Pauline H B
authors.initials: PH
authors.lastname: Kok
authors.forename: Marilette
authors.initials: M
authors.lastname: Stehouwer
authors.forename: Mona K
authors.initials: MK
authors.lastname: Garvin
authors.forename: Milan
authors.initials: M
authors.lastname: Sonka
authors.forename: J Hans
authors.initials: JH
authors.lastname: DeVries
authors.forename: Reinier O
authors.initials: RO
authors.lastname: Schlingemann
authors.forename: Michael D
authors.initials: MD
authors.lastname: Abràmoff
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000473:pathology*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012162:Retinal Degeneration / Q000209:etiology / Q000473:pathology*; D055351:Retinal Neurons / Q000473:pathology; D012307:Risk Factors; D041623:Tomography, Optical Coherence
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human