title: Regular aspirin use and retinal microvascular signs: the Blue Mountains Eye Study.
abstract: OBJECTIVE
  Hypertension is closely related to microvascular abnormalities and there is increasing interest in agents that target the microvasculature. The effect of aspirin on the microvasculature has not been well studied. We examined the cross-sectional and longitudinal associations between regular aspirin use and retinal microvascular signs.
  
  
  METHODS
  We digitized retinal photographs from participants of the Blue Mountains Eye Study cohort (1992-1994, n = 3654, aged over 49 years, and 1997-1999, n = 2335) and used a computer-assisted method to measure average retinal arteriolar and venular diameters. Information on the frequency of aspirin use was collected, with regular aspirin use defined as weekly or daily.
  
  
  RESULTS
  Regular aspirin users comprised 21.2% (n = 775) of the baseline population. At baseline and in individuals who were on one or more antihypertensive medication, regular aspirin use was found to be associated with retinal arterioles on average 3.6 mum (95% confidence interval 1.0, 6.2) wider than those of non-users or occasional aspirin users, after adjusting for age, blood pressure, smoking, diabetes, non-steroidal anti-inflammatory drug use and other variables. Increasing frequency of aspirin use was associated with increasing retinal arteriolar diameter (Ptrend < 0.01). At 5-year follow-up, regular users of aspirin and antihypertensive medication(s) had wider retinal arterioles than those who used aspirin less regularly. Neither antihypertensive medication use alone nor aspirin use alone was associated with wider retinal vessels.
  
  
  CONCLUSIONS
  Our finding of a possible association between the combined use of aspirin and antihypertensive agent(s) and wider retinal arteriolar diameter warrants further investigation into the effects of aspirin on the microvasculature.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology (Westmead Hospital), the Westmead Millennium Institute, University of Sydney, Australia.
authors.forename: Gerald
authors.initials: G
authors.lastname: Liew
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Leeder
authors.forename: Wayne
authors.initials: W
authors.lastname: Smith
authors.forename: Tien Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001160:Arterioles / Q000187:drug effects* / Q000503:physiopathology; D001241:Aspirin / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D010781:Photography / Q000379:methods; D012164:Retinal Diseases / Q000188:drug therapy; D012171:Retinal Vessels / Q000187:drug effects* / Q000503:physiopathology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin