%0 Journal Article
%T Vitamin D Deficiency Is Not Associated with Changes in Retinal Geometric Parameters in Young People with Type 1 Diabetes
%A Myra Poon
%A Maria E. Craig
%A Harleen Kaur
%A Janine Cusumano
%A Muhammad Bayu Sasongko
%A Tien Yin Wong
%A Kim C. Donaghue
%J Journal of Diabetes Research
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/280691
%X Changes in retinal geometric parameters predict risk and progression of diabetic retinopathy (DR). We have shown that vitamin D deficiency (VDD) is associated with DR. We hypothesized that VDD mediates changes in retinal geometric parameters. Retinal vascular geometric parameters were assessed using a semiautomated computer program in photographs from young people with type 1 diabetes (T1D) and summarized as central retinal arteriolar and venular equivalents (CRAE, CRVE), fractal dimension, length-diameter ratio, branching angle and curvature tortuosity. Parameters were compared between those with and without DR and VDD (25-hydroxyvitamin D concentration ¡Ü 50£¿nmol/L). Retinal vascular geometric parameters were also compared across quartiles of vitamin D levels. Median CRVE was higher in patients with DR compared with those without (median (IQR) CRVE 247.3£¿¦Ìm (31.3) versus 238.8£¿¦Ìm (23.5), ). Fractal dimension was marginally greater in patients without VDD (1.49 (0.06) versus 1.47 (0.07) ). There was no difference in CRAE, CRVE, length-diameter ratio, branching angle, and curvature tortuosity between those with and without VDD and across quartiles of 25OHD. In conclusion, DR is associated with higher CRVE in young people with T1D; however, VDD is not associated with changes in retinal vascular geometric measures, suggesting an earlier role in the time course of DR pathogenesis. 1. Introduction Despite improvements in treatment, diabetic retinopathy (DR) remains a significant complication of type 1 diabetes (T1D). Identification of early treatable predictors of DR, may allow more aggressive management of those at high risk. There is increasing evidence that vitamin D deficiency (VDD) may play a role in pathogenesis of DR. In adults with type 2 diabetes, lower 25-hydroxyvitamin D (25OHD) levels have been associated with proliferative DR [1, 2]. We have shown that VDD is associated with a twofold increased risk of DR (OR 2.12, 95% CI 1.03¨C4.33) independent of diabetes duration and HbA1c [3]. Changes in retinal microvascular geometry can be used to predict DR prior to the development of microaneurysms or hemorrhage [4, 5]. These retinal measurements include retinal arteriolar and venular calibers, vessel tortuosity, length-diameter ratio, branching angles, and fractal dimension. In the Wisconsin Epidemiology Study of Diabetic Retinopathy (WESDR), an increase in retinal venular caliber of 10£¿¦Ìm was associated with higher 6-year incidence of DR, progression of DR, and incidence of proliferative DR [6]. Longitudinal studies from our group have demonstrated that
%U http://www.hindawi.com/journals/jdr/2013/280691/