title: Retinal vascular fractals and microvascular and macrovascular complications in type 1 diabetes.
abstract: OBJECTIVE
  Fractal analysis is a method to quantify the geometric pattern and complexity of the retinal vessels. This study examined the association of retinal fractal dimension (D(f)) and microvascular and macrovascular complications in a population-based cohort of Danish patients with type 1 diabetes.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  This was a cross-sectional study of 208 long-term surviving type 1 diabetes patients from a population-based Danish cohort identified in 1973.
  
  
  METHODS
  Retinal photographs were obtained at a clinical examination in 2007 or 2008. D(f) was measured with a semiautomatic computer-based program (International Retinal Imaging Software; National University of Singapore, Republic of Singapore; University of Sydney, Sydney, and University of Melbourne, Melbourne, Australia). D(f) of the retinal vasculature was measured within a predefined circular region of 3.5 optic disc radii centered on the optic disc. Line tracing of the vasculature was provided by the program. Any artifacts were removed by the grader, and the box-counting method then was used by the program to calculate D(f).
  
  
  METHODS
  The association of D(f) with proliferative retinopathy, nephropathy, neuropathy, and macrovascular disease (coronary heart disease, stroke, peripheral artery disease) was examined.
  
  
  RESULTS
  Retinal fractals were gradable in at least 1 eye in 178 (86.6%) of 208 patients. Median age and duration of diabetes for these patients were 57.8 years and 42 years, respectively. Median D(f) was 1.4610 (range, 1.3774-1.5188). After adjustments for age, gender, duration of diabetes, systolic blood pressure, and smoking, persons with lower D(f) were more likely to have proliferative retinopathy (odds ratio [OR], 1.45 per standard deviation [SD] decrease in D(f); 95% confidence interval [CI], 1.04-2.03) and neuropathy (OR, 1.42 per SD decrease in D(f); 95% CI, 1.01-2.01). There was also a trend of an association between lower D(f) and nephropathy (OR, 1.39 per SD decrease in D(f); 95% CI, 0.97-2.01) but not macrovascular disease. Furthermore, persons with lower D(f) were older.
  
  
  CONCLUSIONS
  This study adds to the evidence that D(f) may have some role as a global measure of retinal vasculature and its association with systemic disease. Prospective studies clarifying this role are needed.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: Department of Ophthalmology, Odense University Hospital, Odense, Denmark. jakob.grauslund@ouh.regionsyddanmark.dk
authors.forename: Jakob
authors.initials: J
authors.lastname: Grauslund
authors.forename: Anders
authors.initials: A
authors.lastname: Green
authors.forename: Ryo
authors.initials: R
authors.lastname: Kawasaki
authors.forename: Lauren
authors.initials: L
authors.lastname: Hodgson
authors.forename: Anne Katrin
authors.initials: AK
authors.lastname: Sjølie
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D017709:Fractals; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010781:Photography; D012161:Retinal Artery / Q000473:pathology*; D012169:Retinal Vein / Q000473:pathology*; D012307:Risk Factors
chemical_list: D006442:Glycated Hemoglobin