title: Hemoglobin concentration is inversely associated with erythrocyte folate concentrations in Colombian school-age children, especially among children with low vitamin B12 status.
abstract: BACKGROUND
  While the majority of cases of nutritional anemia in developing countries are caused by iron deficiency, other micronutrient deficiencies may also be involved. In Colombia, it was recently reported that 38% of school children were anemic; yet, the rate of iron deficiency was only 3.6%.
  
  
  OBJECTIVE
  To determine if micronutrients other than iron were responsible for low hemoglobin concentrations in Colombian school children.
  
  
  METHODS
  We examined hemoglobin concentrations in relation to plasma ferritin, vitamin A, vitamin B12, and erythrocyte folate levels in a representative sample of 2812 low- and middle-income children (5-12 years) from Bogotá, Colombia.
  
  
  RESULTS
  In multivariate analysis, hemoglobin concentration was positively associated with child's age, mother's age, household's socioeconomic stratum, and family income. Low ferritin was related to 3.6 g/l lower hemoglobin concentration (95% confidence interval=-6.0, -1.3). Unexpectedly, we found an inverse trend in hemoglobin concentration by quartiles of erythrocyte folate; the adjusted hemoglobin concentration difference between the highest and lowest folate quartiles was -6.0 g/l (95% confidence interval=-7.2, -4.9; P for trend <0.0001). This difference was greatest among children with vitamin B12 concentration <148 pmol/l (-11.5 g/l), followed by children with vitamin B12 concentration 148-221 pmol/l (-7.7 g/l), and smallest in children with vitamin B12 concentration >221 pmol/l (-5.7 g/l); P for interaction=0.04.
  
  
  CONCLUSIONS
  Hemoglobin concentration is inversely related to erythrocyte folate concentrations in a setting where folate fortification was adopted more than a decade ago. The impact of improving vitamin B12 status on this inverse relationship should be examined.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Arsenault
authors.forename: M
authors.initials: M
authors.lastname: Mora-Plazas
authors.forename: Y
authors.initials: Y
authors.lastname: Forero
authors.forename: S
authors.initials: S
authors.lastname: Lopez-Arana
authors.forename: A
authors.initials: A
authors.lastname: Baylin
authors.forename: E
authors.initials: E
authors.lastname: Villamor
mesh_terms: D000740:Anemia / Q000196:embryology* / Q000517:prevention & control; D002648:Child; D002675:Child, Preschool; D003105:Colombia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D005293:Ferritins / Q000097:blood; D005492:Folic Acid / Q000097:blood*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D014801:Vitamin A / Q000097:blood; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D006454:Hemoglobins; D014801:Vitamin A; D005293:Ferritins; D005492:Folic Acid; D014805:Vitamin B 12