title: Relationships between age, blood pressure, and retinal vessel diameters in an older population.
abstract: OBJECTIVE
  To describe the cross-sectional relationships between age, blood pressure (BP), and quantitative measures of retinal vessel diameters in an older Australian population.
  
  
  METHODS
  Retinal photographs from right eyes of participants (n = 3654, aged 49+ years) in the Blue Mountains Eye study taken during baseline examinations (1992-1994) were digitized. The width of all retinal vessels located 0.5 to 1.0 disc diameters from the disc margin was measured by a computer-assisted method. Summarized estimates for central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) represent average retinal vessel diameters. The arteriole-to-venule ratio (AVR) was calculated. Associations between age and BP and CRAE, CRVE, and AVR were assessed with generalized linear models.
  
  
  RESULTS
  Retinal vessel diameters decreased with increasing age in both men and women. CRAE and CRVE decreased by 4.8 microm and 4.1 microm, respectively, per decade increase in age, after adjusting for sex and mean arterial blood pressure. Mean AVR declined by 0.01 for each increasing decade of age, until 79 years. After adjustment for age, sex, smoking, and body mass index, CRAE, CRVE and AVR were all significantly and inversely associated with BP. For every 10-mm Hg increase in mean arterial blood pressure, AVR decreased by 0.012 and CRAE and CRVE decreased by 3.5 microm and 0.96 microm, respectively.
  
  
  CONCLUSIONS
  Retinal arteriolar and venular diameters narrow with increasing age, and these parameters are inversely related to BP, independent of age, gender, and smoking. The findings are consistent with those from the Atherosclerosis Risk in Communities Study suggesting that decreased retinal vessel diameters may reflect microvascular damage from elevated blood pressure.
authors.affiliation: Department of Ophthalmology, Centre for Vision Research, and the Westmead Millennium and Save Sight Institutes, the University of Sydney, NSW, Australia.
authors.forename: Harry
authors.initials: H
authors.lastname: Leung
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
authors.forename: Elena
authors.initials: E
authors.lastname: Rochtchina
authors.forename: Ava G
authors.initials: AG
authors.lastname: Tan
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Larry D
authors.initials: LD
authors.lastname: Hubbard
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010781:Photography; D012164:Retinal Diseases / Q000503:physiopathology*; D012171:Retinal Vessels / Q000503:physiopathology*