Cognitive Performance and Diabetic Retinopathy: What Your Eyes Can Reveal About Your Brain

Abstract

Background: Diabetic retinopathy (DR) is a chronic diabetes complication. People with Type 2 Diabetes Mellitus (T2DM) have two times the risk for dementia, suggesting it is a new chronic diabetes complication Objective: Evaluate the association of DR with cognitive performance in a T2DM population. Methods: Cross-sectional study with 251 T2DM adults from whom socio-demographic, clinical, laboratory data, a screening test for depression symptoms [Patient Health Questionaire-9 (PHQ-9)], Mini-Mental State Examination (MMSE), Semantic Verbal Fluency Test, Trail Making Test A and B, Word Memory test were collected and performed. All cognitive test scores were converted into Global Cognition z-Score [GCS(z)]. The association between GCS(z) < 0 with DR was performed using a multivariate binary logistic regression model adjusted for age ≥ 65 years, school years ≤ 6 years, DM duration ≥ 10 years, depression symptoms score > 9 at PHQ-9, arterial hypertension, physical activity, diabetic retinopathy, macular edema, and cardiovascular disease. Results: After exclusions, the 251 eligible patients were 56.6% female, with a mean age of 61.1(±9.8) years, DM duration of 12.6(±8.9) years, and 7.6(±4.2) years of school education. DR prevalence was 46.5%. Multivariate Logistic Regression Model showed an association between DR and GCS(z) < 0, with odds ratio (CI95%) of 2.50 (1.18-5.34), adjusted for age, low education level, arterial hypertension and depression symptoms [OD and CI95% respectively: 5.46(2.42-12.34); 12.19(5.62-26.46); 2.55(0.88-7.39); 3.53(1.55-8.07)]. Conclusion: In this T2DM population, having DR increased the chance for worse cognitive performance even when adjusted for age, low education level, presence of arterial hypertension, and depression symptoms.

Diabetic rats with high levels of endogenous dopamine do not show retinal vascular pathology

“…Diabetes causes cognitive and motor deficits in addition to retinal deficits ( van Duinkerken et al, 2009 ; Haan et al, 2012 ; Sherin et al, 2012 ; de Almeida Faria et al, 2022a , b ; Rhmari Tlemçani et al, 2022 ). In fact, DR presence and severity have been associated with increased cortical atrophy ( Wessels et al, 2006 ; Hansen et al, 2022 ), cerebral ischemia ( Haan et al, 2012 ) and microinfarcts ( Lee et al, 2019 ), and structural changes in the brain ( Ferguson et al, 2003 ; Wang et al, 2019 ).…”

“…In fact, DR presence and severity have been associated with increased cortical atrophy ( Wessels et al, 2006 ; Hansen et al, 2022 ), cerebral ischemia ( Haan et al, 2012 ) and microinfarcts ( Lee et al, 2019 ), and structural changes in the brain ( Ferguson et al, 2003 ; Wang et al, 2019 ). Behavioral changes associated with DR include accelerated cognitive decline ( Ding et al, 2010 ) and deficits in information processing, concentration, and attention ( Ferguson et al, 2003 ; de Almeida Faria et al, 2022a , b ; Rhmari Tlemçani et al, 2022 ). Tracking the temporal progression of deficits allows us to determine whether retinal neuronal changes can be used as an early detector for later cognitive, motor, or retinal vascular changes.…”