An important public health problem: Vitamin b12 deficiency

Abstract

Introduction: We observed increased methylmalonic acid (MMA) excretion in urine in some cases referred to the centre by the Ministry of Health on suspicion of phenylketonuria and biotinidase deficiency detected by newborn screening. The etiology of increased urine MMA in almost all patients was vitamin B12 deficiency. Because vitamin B12 deficiency could cause severe neurological damage, we need to report its frequency for the cases referred to the outpatient clinic in this study. In addition, the previous studies on vitamin B12 deficiency mostly represent the cases with hematological findings and there is not enough research concerning infants with no complaints considered healthy by their families. Therefore, we also aimed to determine serum normal lower limit of vitamin B12 in this study.Methods: The study group consisted of 215 infants who had been tested for serum B12 level during the first 4 months of life out of 335 cases referred to the centre from June 2011 to June 2016 as a part of the screening program put in place by the Ministry of Health.Results: Vitamin B12 deficiency was determined in 48.8 % of the cases. Mean plasma homocystein, C3-carnitine, and urine MMA was significantly higher in patients with vitamin B12 deficiency. Lower limit of normal vitamin B12 in serum that did not cause elevation of serum homocystein was found 257 pg/mL, and the limit that did not cause elevation of urine MMA was 219 pg/mL.Discussion and Conclusion: Vitamin B12 deficiency may only manifest itself with neurological symptoms without any hematological findings, and some of those symptoms may be irreversible even after vitamin B12 supplementation. In populations with poor socioeconomic status such as ours, where B12 deficiency is common, women in childbearing age should be supported with vitamin B12 in cases of deficiency before pregnancy.