Background: During infancy, minor developmental delays and gastrointestinal complaints are common, as is a biochemical profile indicative of impaired cobalamin status.
Objective: We investigated whether cobalamin supplementation can improve development or symptoms in infants with biochemical signs of impaired cobalamin function and developmental delay or feeding difficulties.
Design: Infants <8 mo of age (n = 105) who were referred for feeding difficulties, subtle neurologic symptoms, or delayed psychomotor development were assessed for cobalamin status [by the measurement of serum cobalamin, plasma total homocysteine (tHcy), and plasma methylmalonic acid (MMA)]. Infants with biochemical signs of impaired cobalamin function, defined as a plasma tHcy concentration ≥6.5 μmol/L (n = 79), were enrolled in a double-blind, randomized controlled trial to receive 400 μg hydroxycobalamin intramuscularly (n = 42) or a sham injection (n = 37). Motor function [Alberta Infants Motor Scale (AIMS)] and clinical symptoms (parental questionnaire) were recorded at entry and after 1 mo.
Results: During follow-up, cobalamin supplementation changed all markers of impaired cobalamin status (ie, plasma tHcy decreased by 54%, and MMA decreased by 84%), whereas no significant changes were seen in the placebo group (P < 0.001). The median (IQR) increase in the AIMS score was higher in the cobalamin group than in the placebo group [7.0 (5.0, 9.0) compared with 4.5 (3.3, 6.0); P = 0.003], and a higher proportion showed improvements in regurgitations (69% compared with 29%, respectively; P = 0.003).
Conclusions: In infants with biochemical signs of impaired cobalamin function, 1 intramuscular injection of cobalamin resulted in biochemical evidence of cobalamin repletion and improvement in motor function and regurgitations, which suggest that an adequate cobalamin status is important for a rapidly developing nervous system. This trial was registered at clinicaltrials.gov as NCT00710359 and NCT00710138.