title: Relationships among diabetic retinopathy, antioxidants, and glycemic control.
abstract: OBJECTIVE
  Type 2 Diabetes Mellitus (DM) is increasing worldwide and affects ∼11% of the Hong Kong population. Diabetic retinopathy (DR) is a common cause of vision loss in type 2 DM. Risk of DR is increased by poor glycemic control, elevated lipids, and blood pressure, but it is not possible to predict the development or progression of DR at an individual level. Increased oxidative stress is thought to play a role. The use of a wider biomarker profile incorporating biomarkers of antioxidant status and oxidative stress may aid identification of individuals at higher risk or at very early stages of developing DR.
  
  
  METHODS
  Four hundred twenty type 2 DM subjects without diabetic complications were investigated. Eyes were examined for DR and anterior and posterior ocular segment pathology. DR was graded according to Early Treatment Diabetic Retinopathy Study criteria. Demographic data were collected. Traditional risk factors plus biomarkers of antioxidant status and oxidative stress in fasting blood and urine were determined.
  
  
  RESULTS
  Overall DR prevalence was 89%. No significant differences in any demographic measures or biomarkers were found among those subjects with different DR grades, or in those without DR. Significant correlations (p < 0.0001) between HbA1c and DNA damage, (ρ = 0.32) and fasting plasma glucose and DNA damage (ρ = 0.52) were seen. DNA damage was also significantly and inversely correlated (p < 0.0001) with both plasma ascorbic acid (ρ = -0.41) and plasma total antioxidant level (ρ = -0.21).
  
  
  CONCLUSIONS
  DR prevalence was very high in this group, but no biomarker differences were seen in those with DR compared to those free of DR, or in those with different degrees of severity of DR. This group of 420 subjects is being followed up to investigate whether the extended biomarker profile at baseline is related to progression of and/or incident DR.
authors.affiliation: School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, SAR of China. carly.lam@polyu.edu.hk
authors.forename: Carly S Y
authors.initials: CS
authors.lastname: Lam
authors.forename: Iris F F
authors.initials: IF
authors.lastname: Benzie
authors.forename: Siu Wai
authors.initials: SW
authors.lastname: Choi
authors.forename: Lily Y L
authors.initials: LY
authors.lastname: Chan
authors.forename: Vincent T F
authors.initials: VT
authors.lastname: Yeung
authors.forename: George C
authors.initials: GC
authors.lastname: Woo
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D004249:DNA Damage; D003924:Diabetes Mellitus, Type 2; D003930:Diabetic Retinopathy / Q000097:blood / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism*; D005215:Fasting / Q000097:blood; D006442:Glycated Hemoglobin; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D018384:Oxidative Stress; D015995:Prevalence; D012307:Risk Factors
chemical_list: D000975:Antioxidants; D001205:Ascorbic Acid; D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human