title: Estrogen replacement therapy and retinal vascular caliber.
abstract: OBJECTIVE
  It is unclear if estrogen replacement therapy (ERT) has an effect on the retinal circulation. In the current study, we examine the association of ERT, female reproductive factors, and retinal vascular caliber.
  
  
  METHODS
  Population-based cross-sectional study.
  
  
  METHODS
  Women participants aged 43 to 84 years living in Beaver Dam, Wisconsin.
  
  
  METHODS
  Retinal photographs of participants taken at the baseline examination were digitized, and the diameters of arterioles and venules were measured using a well-established technique. Estrogen replacement therapy and female reproductive factors were ascertained by interview.
  
  
  METHODS
  Retinal arteriolar and venular diameters.
  
  
  RESULTS
  Of the 2469 women participants with data for analysis, 10.5% were current users of ERT and 7.4% were past users. After adjusting for age, blood pressure (BP), body mass index, smoking, and other factors, women who were current users of ERT had narrower retinal arteriolar and venular diameters than those who were past users or never used, with mean arteriolar diameters of 167.6 microm for current users, 170.8 microm for past users, and 170.9 microm for those who never used (P = 0.009) and mean venular diameters of 239.9 microm for current users, 244.0 microm for past users, and 243.9 microm for those who never used (P = 0.02). There was a significant trend of increasing narrowing for both arterioles (P trend, 0.01) and venules (P trend, 0.007) with increasing duration of ERT. Associations were somewhat stronger in younger women and women without a history of hypertension and cigarette smoking. Female reproductive factors (e.g., age of menarche and pregnancy) were not associated with retinal vessel diameters.
  
  
  CONCLUSIONS
  Estrogen replacement therapy is associated with narrower retinal vessel diameters, independent of BP and other vascular factors.
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia. ophwty@nus.edu.sg
authors.forename: Tien Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Michael D
authors.initials: MD
authors.lastname: Knudtson
authors.forename: Barbara E K
authors.initials: BE
authors.lastname: Klein
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Larry D
authors.initials: LD
authors.lastname: Hubbard
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001160:Arterioles / Q000473:pathology; D001794:Blood Pressure; D015992:Body Mass Index; D003251:Constriction, Pathologic; D003430:Cross-Sectional Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D012039:Regional Blood Flow; D017584:Reproductive History; D012171:Retinal Vessels / Q000473:pathology*; D012307:Risk Factors; D012907:Smoking; D014699:Venules / Q000473:pathology