title: The influence of iron, vitamin B(12), and folate levels on soluble transferrin receptor concentration in pregnant women.
abstract: BACKGROUND
  Soluble transferrin receptor (sTfR) concentration is high in iron deficiency and in conditions of increased erythropoiesis. In developing countries like Brazil, pregnant women usually have concurrent iron, vitamin B(12), and folate deficiencies. This study investigated the relationship between serum sTfR concentration and iron, vitamin B(12), and folate status in pregnant women.
  
  
  METHODS
  The concentration of the sTfR, hematocrit (Hct), hemoglobin (Hb), red blood cell (RBC) and white blood cell (WBC) counts, serum iron (SI), total iron-binding capacity (TIBC), transferrin saturation, serum ferritin, zinc protoporphyrin (ZPP), vitamin B(12), and serum and RBC folate were determined in 40 healthy pregnant women who delivered term babies.
  
  
  RESULTS
  sTfR concentration was significantly higher when the women had iron deficiency (serum ferritin <10 microg/l, p<0.01), but there was no significant difference in sTfR concentration according to vitamin B(12), serum, and RBC folate concentrations. Women who had serum ferritin <10 microg/l also had lower vitamin B(12) values (p<0.01). There was no significant correlation between vitamin B(12) and serum folate with sTfR concentration. According to a regression analysis, sTfR concentration was associated with serum iron, serum ferritin, RBC count, and hemoglobin concentration.
  
  
  CONCLUSIONS
  Iron was the only micronutrient that influenced the sTfR concentration. Vitamin B(12) and folate concentrations were probably not sufficiently low to have an impact on the sTfR concentration.
authors.affiliation: Department of Nutrition, Faculdade de Saúde Pública, School of Public Health, University of São Paulo, Av. Dr. Arnaldo 715, Cerqueira César, SP, CEP-01246-904, São Paulo, Brazil. aapaiva@yahoo.com.br
authors.forename: Adriana
authors.initials: A
authors.lastname: de Azevedo Paiva
authors.forename: Patrícia H C
authors.initials: PH
authors.lastname: Rondó
authors.forename: Elvira M
authors.initials: EM
authors.lastname: Guerra-Shinohara
authors.forename: Camila S
authors.initials: CS
authors.lastname: Silva
mesh_terms: D000328:Adult; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005293:Ferritins / Q000097:blood; D005492:Folic Acid / Q000097:blood*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000097:blood*; D011247:Pregnancy; D011990:Receptors, Transferrin / Q000097:blood*; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D006454:Hemoglobins; D011990:Receptors, Transferrin; D005293:Ferritins; D005492:Folic Acid; D007501:Iron; D014805:Vitamin B 12