Low vitamin B 12 blood levels in sickle cell disease: Data from a large cohort study in Tanzania.

Sickle cell disease (SCD) is associated with high rates of undernutrition and stunting. Undernutrition in combination with chronic haemolysis may lead to deficiencies in micronutrients necessary for erythropoiesis. Here we examined selected levels of ferritin, vitamins B 2 , B 6 , B 9 and B 12 , and vitamin C that were measured in blood samples from 820 SCD patients from Tanzania with no history of hospital admission, infections or painful episodes in the previous 30 days. We studied children (0-8 years), early adolescents (9-14 years), late adolescents (15-17 years) and adults (≥18 years). Severely low levels of vitamin B 12 were observed across the four age groups. Despite the lowered vitamin B 12 concentrations, total homocysteine concentrations were normal across both genders in all age groups. We found no significant gender-related differences between the other measured micronutrients. In this large SCD population, spanning the whole life cycle, a low level of vitamin B 12 was consistently found across both genders and all age groups. Given the pivotal role of vitamin B 12 in cellular metabolism, particularly in erythropoiesis, more studies are required to unravel how to better detect clinically relevant vitamin B 12 deficiency among SCD patients, and thus to identify more precisely those who need supplementation of vitamin B 12 .