Causes of vitamin B12 deficiency

Tunis Med. 2015 Nov;93(11):678-82.


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.

Study 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.

Conclusion: 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.