Low serum vitamin B12 is common in coeliac disease and is not due to autoimmune gastritis.

OBJECTIVE

Although coeliac disease is a disorder of the proximal small bowel, associated vitamin B12 deficiency has been reported. This study aimed to assess the prevalence of B12 deficiency in a large series of coeliac patients, and to exclude the possibility that it is due to associated autoimmune gastritis.

DESIGN

Prospective routine measurement of serum B12 in coeliac patients, with investigations for pernicious anaemia/autoimmune gastritis in B12-deficient patients.

SETTING

Gastroenterology department of a large district general hospital.

INTERVENTIONS: If they were not taking vitamin B12 supplements already, patients had serum B12 measured before starting dietary gluten exclusion. Those with low levels also had gastric biopsies taken and plasma gastrin and serum gastric parietal cell and intrinsic factor antibodies measured.

MAIN OUTCOME MEASURES: Prevalence of low serum B12, and presence or absence of indicators of pernicious anaemia/autoimmune gastritis in patients with low serum B12.

RESULTS

Of 159 patients, 13 had low serum B12 at diagnosis. A further six had been receiving B12 replacement therapy for 3-37 years before diagnosis, giving an overall prevalence of 12% (19 patients). Only 2/19 patients had gastric corpus atrophy, one with intrinsic factor antibodies and the other with hypergastrinaemia. There was no relationship between low B12 and clinical characteristics.

CONCLUSIONS

Low B12 is common in coeliac disease without concurrent pernicious anaemia, and may be a presenting manifestation. B12 status should be known before folic acid replacement is started.