title: Predictors of hemoglobin in Danish blood donors: results from the Danish Blood Donor Study.
abstract: BACKGROUND
  It is well known that blood donors are at increased risk of iron deficiency and subsequent development of iron deficiency anemia. We aimed to investigate the effect of factors influencing hemoglobin (Hb) levels.
  
  
  METHODS
  Initiated in 2010, the Danish Blood Donor Study is a population-based study and biobank. We performed multivariable linear regression analysis to assess the effects of donation activity, physiologic and lifestyle factors, and diet on Hb levels among 15,197 donors. We also performed multivariable logistic regression to evaluate the effects of these factors on the risk of having low Hb (defined as Hb below the 10th percentile among men and women, respectively) and of a decrease in Hb greater than 0.5 mmol/L (0.8 g/dL) between successive donations. All analyses were performed stratified for sex and smoking status. We also tested a previously used model for the prediction of Hb.
  
  
  RESULTS
  The strongest predictors of Hb and risk of low Hb were low ferritin (<15 ng/mL) and current use of iron supplementation (yes/no). No dietary factors were found to be consistently significant in multivariable models predicting Hb levels, risk of having low Hb, or risk of a decrease in Hb greater than 0.5 mmol/L. We found similar effects to previous studies of factors in the predictive model, with little additional effect of including smoking status and ferritin.
  
  
  CONCLUSIONS
  As ferritin was the strongest predictor of Hb, this study supports the implementation of regular ferritin measurement as a method of risk assessment among blood donors.
authors: Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark.
authors: Sebastian R
authors: SR
authors: Kotzé
authors: Department of Clinical Immunology, Naestved Hospital, Naestved, Denmark.
authors: Ole B
authors: OB
authors: Pedersen
authors: Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark.
authors: Mikkel S
authors: MS
authors: Petersen
authors: Department of Clinical Immunology, Copenhagen University Hospital.
authors: Erik
authors: E
authors: Sørensen
authors: Department of Clinical Immunology, Copenhagen University Hospital.
authors: Lise W
authors: LW
authors: Thørner
authors: Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark.
authors: Cecilie J
authors: CJ
authors: Sørensen
authors: Department of Clinical Immunology, Copenhagen University Hospital.
authors: Andreas S
authors: AS
authors: Rigas
authors: Department of Epidemiological Research, Statens Serum Institut, Copenhagen, Denmark.
authors: Henrik
authors: H
authors: Hjalgrim
authors: Department of Epidemiological Research, Statens Serum Institut, Copenhagen, Denmark.
authors: Klaus
authors: K
authors: Rostgaard
authors: Department of Clinical Immunology, Copenhagen University Hospital.
authors: Henrik
authors: H
authors: Ullum
authors: Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark.
authors: Christian
authors: C
authors: Erikstrup
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000209:etiology / Q000517:prevention & control*; D001782:Blood Donors / Q000706:statistics & numerical data*; D015992:Body Mass Index; D015331:Cohort Studies; D003276:Contraceptives, Oral; D003718:Denmark; D004032:Diet; D004363:Drug Utilization / Q000706:statistics & numerical data; D005260:Female; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D017584:Reproductive History; D012307:Risk Factors; D012727:Sex Characteristics; D012907:Smoking / Q000097:blood; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D003276:Contraceptives, Oral; D006454:Hemoglobins; D005293:Ferritins