Diminished vitamin B12 levels in patients with severe sickle cell disease

Abstract

The aim of this study was to estimate the levels of vitamin B12 in patients with severe sickle cell disease compared to normal controls. Complete blood count, iron studies and vitamin B12 levels were obtained in 85 consecutive patients with severe sickle cell disease (56 males, 29 females, aged 14-49 years) and 100 healthy blood donors (67 males, 33 females, aged 17-60 years) as a normal control group. Thirty-seven of the 85 patients (43.5%) had serum vitamin B12 levels below normal values (mean 84.3 +/- 28.7, range 7-145 pmol L-1) without macrocytosis or hypersegmented neutrophils. The mean level of vitamin B12 in the remaining 48 patients (56.5%) was normal (mean 233.3 +/- 73.9, range 152-435 pmol L-1) which is below the mean of normal control levels (mean 327.7 +/- 168.7, range 178-897 pmol L-1). Patients with low B12 achieved a significant symptomatic improvement when treated with vitamin B12, 1 mg intramuscularly weekly for 12 weeks when compared with patients with normal B12 levels. We conclude that many patients with severe sickle cell disease may suffer from unrecognized vitamin B12 deficiency.