title: The anemia of vitamin A deficiency: epidemiology and pathogenesis.
abstract: OBJECTIVE
  To gain insight into vitamin A deficiency as a cause of anemia.
  
  
  METHODS
  Comprehensive review of the scientific literature.
  
  
  RESULTS
  Although vitamin A deficiency is recognized to cause anemia, 'vitamin A deficiency anemia' lacks complete characterization as a distinct clinical entity. Vitamin A appears to be involved in the pathogenesis of anemia through diverse biological mechanisms, such as the enhancement of growth and differentiation of erythrocyte progenitor cells, potentiation of immunity to infection and reduction of the anemia of infection, and mobilization of iron stores from tissues. Epidemiological surveys show that the prevalence of anemia is high in populations affected by vitamin A deficiency in developing countries. Improvement of vitamin A status has generally been shown to reduce anemia, but the actual public health impact on anemia is unclear.
  
  
  CONCLUSIONS
  Further work is needed to elucidate the biological mechanisms by which vitamin A causes anemia. The inclusion of anemia as an outcome measure in future micronutrient intervention studies should help provide further insight into the anemia of vitamin A deficiency.
authors.affiliation: Department of Ophthalmology Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. rdsemba@jhmi.edu
authors.forename: R D
authors.initials: RD
authors.lastname: Semba
authors.forename: M W
authors.initials: MW
authors.lastname: Bloem
mesh_terms: D000293:Adolescent; D000328:Adult; D000740:Anemia / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011247:Pregnancy; D014802:Vitamin A Deficiency / Q000150:complications / Q000453:epidemiology* / Q000473:pathology*