title: Mitochondrial Haplogroups Affect Severity But Not Prevalence of Diabetic Retinopathy.
abstract: We previously reported European mitochondrial haplogroup H to be a risk factor for and haplogroup UK to be protective against proliferative diabetic retinopathy (PDR) among Caucasian patients with diabetic retinopathy (DR). The purpose of this study was to determine whether these haplogroups are also associated with the risk of having DR among Caucasian patients with diabetes.
  
  
  
  Deidentified medical records for 637 Caucasian patients with diabetes (223 with DR) were obtained from BioVU, Vanderbilt University's electronic, deidentified DNA databank. An additional 197 Caucasian patients with diabetes (98 with DR) were enrolled from the Vanderbilt Eye Institute (VEI). We tested for an association between European mitochondrial haplogroups and DR status.
  
  
  
  The percentage of diabetes patients with DR did not differ across the haplogroups (P = 0.32). The percentage of patients with nonproliferative DR (NPDR; P = 0.0084) and with PDR (P = 0.027) significantly differed across the haplogroups. In logistic regressions adjusting for sex, age, diabetes type, duration of diabetes, and hemoglobin A1c, neither haplogroup H nor haplogroup UK had a significant effect on DR compared with diabetic controls. Haplogroup UK was a significant risk factor (OR = 1.72 [1.13-2.59], P = 0.010) for NPDR compared with diabetic controls in the unadjusted analysis, but not in the adjusted analysis (OR = 1.29 [0.79-2.10], P = 0.20).
  
  
  
  Mitochondrial haplogroups H and UK were associated with severity, but not presence, of DR. These data argue that the effect of these haplogroups is related to ischemia and neovascularization, the defining features of PDR.
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: Jana A
authors.initials: JA
authors.lastname: Bregman
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Herren
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Estopinal
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: Isaac M
authors.initials: IM
authors.lastname: Chocron
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: Paula A
authors.initials: PA
authors.lastname: Harlow
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: Cassandra
authors.initials: C
authors.lastname: Warden
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.
authors.forename: Milam A
authors.initials: MA
authors.lastname: Brantley
authors.affiliation: Vanderbilt Genetics Institute and Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Samuels
mesh_terms: D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000097:blood / Q000235:genetics*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006239:Haplotypes; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics*; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D006113:United Kingdom / Q000453:epidemiology; D044465:White People
chemical_list: D006442:Glycated Hemoglobin