title: Causes of vitamin B12 deficiency.
abstract: BACKGROUND
  B12 Vitamin deficiency is common in adults (20% of general population of industrialized populations), especially in elderly patients (30-40%). The etiologies of Vitamin B12 deficiency have been dominated by the cobalamin syndrome nutrient and the Biermer disease, rarely by the intake or nutritional deficiency and bad absorptions.
  
  
  OBJECTIVE
  Establish an etiology of vitamin B12 in a Tunisian population Methods: In a prospective study involving 100 patients with macrocytic anemia, a comprehensive assessment has been carried out of: B12 vitamin and folate intake, homocysteine, immunological assessment (antibodies, intrinsic anti-factor and anti-gastric parietal cells), an endoscopic exploration, and a dietary nutritional survey.
  
  
  RESULTS
  The mean age of patients was 53.6 ± 17,6 years (13 - 88 years), the gender ratio (female/male) is 1.22. The clinical symptomatology shows a functional anemia syndrome in 89% of cases, a digestive syndrome in 88% of cases, and neurological disorders in 67% of cases. The intake of B12 vitamin was reduced (<180 pg/ml) in 99 patients, associated with a hyperhomocysteinemia in 81.63% of cases.The intrinsic anti-factor antibodies were positives in 32 patients, and the antibody anti-gastric parietal cells in 85 patients. Gastric biopsy was performed in 54 patients, showing a chronic atrophic gastritis of fundic localization in 44 patients, antral in 5 patients and pan- gastric in 3 patients. The diagnosis of Biermer anemia was held in 75% of patients, that of FCS in 16% of patients, and a lack of intake in 8% of patients. The etiology was undetermined in 1% of cases.
  
  
  CONCLUSIONS
  Vitamin B12 deficiency is common in the general population, its causes and origins are multiple, we list them in order of occurrence: Biermer disease, the FCS, and the intake deficiency in our population.
authors.forename: Amel
authors.initials: A
authors.lastname: Belghith
authors.forename: Sonia
authors.initials: S
authors.lastname: Mahjoub
authors.forename: Neila
authors.initials: N
authors.lastname: Ben Romdhane