title: The relationship between diabetic retinopathy and cognitive impairment.
abstract: OBJECTIVE
  Recent studies have shown an increased risk for cognitive impairment and dementia in patients with diabetes. An association between diabetic retinopathy (DR) and retinal microvasculature disease and cognitive impairment has been reported as potential evidence for a microvascular component to the cognitive impairment. It was hypothesized that severity of DR would be associated with cognitive impairment in individuals with type 2 diabetes.
  
  
  METHODS
  Three hundred eighty patients with type 2 diabetes were recruited from a population-based eye screening program and grouped by severity of DR as follows: no/mild DR (n=252) and proliferative diabetic retinopathy (PDR) (n=128). Each participant underwent psychosocial assessment; depression screening; ophthalmic and physical examination, including blood assays; and cognitive assessment with the Addenbrooke's Cognitive Examination-Revised (ACE-R), Mini-Mental State Examination (MMSE), and the Mini-Cog. General linear modeling was used to examine severity of DR and cognitive impairment, adjusting for confounders.
  
  
  RESULTS
  Severity of DR demonstrated an inverse relationship with cognitive impairment (fully adjusted R2=0.415, P<0.001). Ethnicity contributed most to the variance observed (16%) followed by education (7.3%) and retinopathy status (6.8%). The no/mild DR group had lower cognitive impairment scores on ACE-R (adjusted mean±SE 77.0±1.9) compared with the PDR group (82.5±2.2, P<0.001). The MMSE cutoff scores showed that 12% of the no/mild DR group (n=31) had positive screening results for dementia or significant cognitive impairment compared with 5% in the PDR group (n=6).
  
  
  CONCLUSIONS
  Patients with minimal DR demonstrated more cognitive impairment than those with advanced DR. Therefore, the increased prevalence of cognitive impairment in diabetes may be associated with factors other than evident retinal microvascular disease.
authors: Corresponding author: Roxanne R. Crosby-Nwaobi, roxanne.crosby-nwaobi@kcl.ac.uk.
authors: Roxanne R
authors: RR
authors: Crosby-Nwaobi
authors: Sobha
authors: S
authors: Sivaprasad
authors: Stephanie
authors: S
authors: Amiel
authors: Angus
authors: A
authors: Forbes
mesh_terms: D000368:Aged; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical
references: J Psychiatr Res. 1975 Nov;12(3):189-98
references: 1202204
references: Diabetes Care. 1995 Jun;18(6):754-60
references: 7555499
references: J Intern Med. 2004 Sep;256(3):183-94
references: 15324362
references: Int J Geriatr Psychiatry. 2006 Nov;21(11):1078-85
references: 16977673
references: J Am Geriatr Soc. 2003 Nov;51(11):1547-53
references: 14687383
references: Diabetes. 1995 Aug;44(8):968-83
references: 7622004
references: Stroke. 2002 Jun;33(6):1487-92
references: 12052979
references: Arch Neurol. 2008 Aug;65(8):1066-73
references: 18695056
references: BMC Endocr Disord. 2008 Dec 11;8:18
references: 19077235
references: Eye (Lond). 2001 Dec;15(Pt 6):719-22
references: 11826989
references: Diabetologia. 2003 Jul;46(7):940-8
references: 12819900
references: Diabetes. 2010 Nov;59(11):2883-9
references: 20798334
references: Neurosci Biobehav Rev. 2004 Apr;28(2):143-80
references: 15172762
references: Diabetes Care. 2003 Jan;26 Suppl 1:S99-S102
references: 12502630
references: JAMA. 1999 Nov 10;282(18):1737-44
references: 10568646
references: Lancet. 1998 Sep 12;352(9131):837-53
references: 9742976
references: J Thorac Cardiovasc Surg. 2005 Mar;129(3):576-83
references: 15746741
references: Arch Ophthalmol. 2001 Jul;119(7):1050-8
references: 11448327
references: Diabetes Care. 2012 Jun;35(6):1279-84
references: 22511257
references: Diabetes Care. 2008 Mar;31(3):544-9
references: 18070990
references: Arch Ophthalmol. 2012 Jul;130(7):895-900
references: 22410630
references: Br J Ophthalmol. 2008 Aug;92(8):1017-25
references: 18614569
references: Endocr Rev. 2008 Jun;29(4):494-511
references: 18436709
references: Arch Neurol. 2003 Oct;60(10):1385-9
references: 14568808
references: J Am Geriatr Soc. 2006 Jun;54(6):898-905
references: 16776783
references: J Am Geriatr Soc. 2003 Oct;51(10):1451-4
references: 14511167
references: Arch Neurol. 2004 May;61(5):661-6
references: 15148141
references: J Am Geriatr Soc. 2001 Mar;49(3):263-9
references: 11300236
references: Diabetes Res Clin Pract. 2012 May;96(2):101-10
references: 22154373
references: Mt Sinai J Med. 2012 Nov-Dec;79(6):664-73
references: 23239205
references: Diabetologia. 2008 Feb;51(2):241-8
references: 18060658
references: J Gen Intern Med. 2001 Sep;16(9):606-13
references: 11556941