title: Tromsø eye study: prevalence and risk factors of diabetic retinopathy.
abstract: OBJECTIVE
  To determine the prevalence of visual impairment, retinopathy and macular oedema, and assess risk factors for retinopathy in persons with diabetes.
  
  
  METHODS
  The present study included 514 participants with diabetes aged 46-87 years from the Tromsø Eye Study, a sub-study of the population-based Tromsø Study in Norway. Visual acuity was measured using an auto-refractor. Retinal images from both eyes were graded for retinopathy and macular oedema. We collected data on risk factor exposure from self-report questionnaires, clinical examinations, laboratory measurements and case note reviews. Regression models assessed the cross-sectional relationship between potential risk factors and diabetic retinopathy.
  
  
  RESULTS
  The prevalence of visual impairment (corrected Snellen visual acuity <20/60 in the better-seeing eye) was 1.6%. The prevalence of diabetic retinopathy was 26.8% and macular oedema 3.9%. In a multivariable logistic regression model, retinopathy was associated with longer diabetes duration (odds ratio, OR 1.07, 95% CI 1.03-1.11), insulin use (OR 2.14, 95% CI 1.19-3.85), nonfasting glucose (OR 1.07, 95% CI 1.00-1.15) and microalbuminuria (OR 1.89, 95% CI 1.28-2.81). Sub-group analyses showed association between retinopathy and even low levels of microalbuminuria (1.16 mg/mmol).
  
  
  CONCLUSIONS
  The findings suggest that low levels of microalbuminuria may be a useful risk predictor for identifying individuals with diabetes at high risk of retinopathy. The study confirms previous findings that insulin use, longer diabetes duration and higher levels of blood glucose are associated with retinopathy in persons with diabetes. The prevalence of diabetic retinopathy was similar as reported in other studies.
authors.affiliation: Department of Ophthalmology and Neurosurgery, University Hospital of North Norway, Tromsø, NorwayResearch Group of Epidemiology of Chronic Diseases, Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, NorwayNIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UKDepartment of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, NorwayDepartment of Nephrology, University Hospital of North Norway, Tromsø, NorwayDepartment of Clinical Medicine, University of Tromsø, Tromsø, NorwayDepartment of Ophthalmology, Odense University Hospital, Odense, DenmarkBrain and Circulation Research Group, Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Bertelsen
authors.forename: Tunde
authors.initials: T
authors.lastname: Peto
authors.forename: Haakon
authors.initials: H
authors.lastname: Lindekleiv
authors.forename: Henrik
authors.initials: H
authors.lastname: Schirmer
authors.forename: Marit D
authors.initials: MD
authors.lastname: Solbu
authors.forename: Ingrid
authors.initials: I
authors.lastname: Toft
authors.forename: Anne Katrin
authors.initials: AK
authors.lastname: Sjølie
authors.forename: Inger
authors.initials: I
authors.lastname: Njølstad
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002784:Cholesterol / Q000097:blood; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology
chemical_list: D002784:Cholesterol; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human