title: Serum estradiol associates with blood hemoglobin in elderly men: the MrOS Sweden study.
abstract: BACKGROUND
  Blood hemoglobin (Hb) declines with age in healthy elderly men, in whom decreasing T has been regarded as part of normal aging. However, the association between Hb and serum estradiol is incompletely known.
  
  
  OBJECTIVE
  To determine whether estradiol is associated with anemia/Hb and established determinants of Hb in elderly men without prostate cancer.
  
  
  METHODS
  The MrOS (Osteoporotic Fractures in Men) is a population-based study (n = 918; median age, 75.3 y; range, 70-81 y).
  
  
  METHODS
  We evaluated total estradiol in relation to Hb and adjusted for potential confounders (ie, age, body mass index [BMI], erythropoietin [EPO], total T, cystatin C, and iron and B-vitamin status).
  
  
  RESULTS
  Estradiol correlated negatively with age (r = -0.14; P < .001). Hb correlated (age adjusted) positively with estradiol (r = 0.21; P < .001) and T (r = 0.10; P < .01). Independent predictors for Hb in multivariate analyses were estradiol, EPO, BMI, transferrin saturation, cystatin C, and free T4, but not T. After exclusion of subjects with Hb <130 g/L and/or T < 8 nmol/L (n = 99), the correlation between Hb and T was no longer significant, whereas the associations between Hb and estradiol remained. After adjusting for age, BMI, and EPO, men with lower estradiol levels were more likely to have Hb in the lowest quartile of values (odds ratio per SD decrease in estradiol = 1.61 [95% confidence interval, 1.34-1.93]). Anemic subjects (Hb < 130 g/L) had lower mean estradiol than nonanemic subjects (67.4 vs 79.4 pmol/L; P < .001).
  
  
  CONCLUSIONS
  Estradiol correlated positively and independently with Hb. Decreased estradiol might partly explain the age-related Hb decline observed in healthy elderly men.
authors.affiliation: Section of Hematology and Coagulation, Department of Internal Medicine, Institute of Medicine (C.L., H.N.-E.), Department of Clinical Chemistry and Transfusion Medicine (S.J.), and Center for Bone and Arthritis Research (CBAR), Geriatric Medicine at the Institute of Medicine (H.J., V.S., M.L., D.M.), Sahlgrenska Academy at the University of Gothenburg, 413 45 Gothenburg, Sweden; Clinical and Molecular Osteoporosis Research Unit (M.K.K.), Department of Clinical Sciences and Orthopaedics, Lund University, SE-20502 Malmö, Sweden; Department of Family and Preventative Medicine (E.B.-C.), University of California, San Diego, California 92093; and CBAR (L.V., C.O.), Department of Internal Medicine and Clinical Nutrition, at the Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, SE-411 45 Gothenburg, Sweden.
authors.forename: Catharina
authors.initials: C
authors.lastname: Lewerin
authors.forename: Herman
authors.initials: H
authors.lastname: Nilsson-Ehle
authors.forename: Stefan
authors.initials: S
authors.lastname: Jacobsson
authors.forename: Helena
authors.initials: H
authors.lastname: Johansson
authors.forename: Valter
authors.initials: V
authors.lastname: Sundh
authors.forename: Magnus K
authors.initials: MK
authors.lastname: Karlsson
authors.forename: Mattias
authors.initials: M
authors.lastname: Lorentzon
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barrett-Connor
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Vandenput
authors.forename: Claes
authors.initials: C
authors.lastname: Ohlsson
authors.forename: Dan
authors.initials: D
authors.lastname: Mellström
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood* / Q000453:epidemiology; D015331:Cohort Studies; D004958:Estradiol / Q000097:blood*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007501:Iron / Q000097:blood; D008297:Male; D058866:Osteoporotic Fractures / Q000097:blood* / Q000453:epidemiology; D013548:Sweden / Q000453:epidemiology; D013739:Testosterone / Q000097:blood; D014804:Vitamin B Deficiency / Q000097:blood / Q000453:epidemiology
chemical_list: D006454:Hemoglobins; D013739:Testosterone; D004958:Estradiol; D007501:Iron