title: Iron stores and vascular function in voluntary blood donors.
abstract: BACKGROUND
  Iron is a pro-oxidant cofactor that may be linked to atherosclerosis progression. Reduction of body iron stores secondary to blood donation has been hypothesized to reduce coronary risk, but retrospective studies have yielded inconsistent findings. We sought to assess the effects of blood donation frequency on body iron stores and physiological and biochemical biomarkers of vascular function associated with atherosclerosis progression.
  
  
  RESULTS
  Forty high-frequency voluntary blood donors (> or =8 donations in past 2 years) and 42 low-frequency blood donors (1 to 2 donations in past 2 years) aged 50 to 75 years were randomly selected from American Red Cross of Connecticut blood donor records. Flow-mediated dilation in the brachial artery, serum markers of iron stores, vascular inflammation and oxidative stress, and cardiac risk factors were assessed in all subjects. Serum ferritin was significantly decreased in high-frequency blood donors when compared with low-frequency blood donors (median values 17 versus 52 ng/mL; P<0.001), but hematocrit did not differ between groups. Flow-mediated dilation in the brachial artery was significantly greater in high-frequency donors when compared with low-frequency donors in univariate analysis (5.5+/-2.6% versus 3.8+/-1.6%; P=0.0003) and in multivariate analysis adjusting for cardiac risk factors and other potential confounders. Serum biomarkers of vascular inflammation did not differ between groups but 3-nitrotyrosine, a marker of oxidative stress, was decreased in high-frequency donors when compared with low-frequency donors.
  
  
  CONCLUSIONS
  High-frequency blood donors had evidence of decreased body iron stores, decreased oxidative stress, and enhanced vascular function when compared with low-frequency donors. These findings support a potential link between blood donation and reduced cardiovascular risk that warrants further investigation in prospective outcome studies.
authors.affiliation: Department of Internal Medicine, Yale University School of Medicine, 135 College St, Suite 301, New Haven, CT 06510, USA.
authors.forename: Haoyi
authors.initials: H
authors.lastname: Zheng
authors.forename: Ritchard
authors.initials: R
authors.lastname: Cable
authors.forename: Bryan
authors.initials: B
authors.lastname: Spencer
authors.forename: Nancy
authors.initials: N
authors.lastname: Votto
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Katz
mesh_terms: D000368:Aged; D050197:Atherosclerosis / Q000453:epidemiology* / Q000378:metabolism* / Q000517:prevention & control; D015415:Biomarkers; D001782:Blood Donors / Q000706:statistics & numerical data*; D001916:Brachial Artery / Q000502:physiology; D005260:Female; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018384:Oxidative Stress; D012307:Risk Factors; D040242:Risk Reduction Behavior; D014664:Vasodilation
chemical_list: D015415:Biomarkers; D007501:Iron