The Effect of Daily Vitamin B-12 Supplementation on the Incidence of Common Childhood Infections in Nepal: Secondary Outcomes from a Double-Blind Randomized Controlled Trial.

BACKGROUND

Vitamin B-12 deficiency is common and affects cell division and differentiation, erythropoiesis, and immune function.

OBJECTIVES

This study aimed to measure the effect of daily vitamin B-12 for 1 y in infants at risk of vitamin B-12 deficiency on the incidence of common infections.

METHODS

This is a predefined, exploratory secondary analysis of a community-based, individually randomized, double-blind, placebo-controlled trial conducted in Bhaktapur, Nepal. We randomly assigned 600, 6-11-mo-old infants in a 1:1 ratio to 2 μg of vitamin B-12 or a placebo daily for 12 mo. We recorded the number of signs and symptoms of 20 common illnesses and the number of visits to the health clinic throughout the 1-y intervention period. Only 26 children were lost to follow-up, and almost 95% of scheduled daily vitamin B-12 doses or placebo were taken. The primary and other key secondary outcomes, including growth, neurodevelopment, cobalamin status, and hemoglobin concentration, have been previously published. In this report, we also reassess the effect of supplementation on biomarker concentrations by baseline vitamin B-12 status.

RESULTS

There were 1474 visits to health clinics in the vitamin B-12 group and 1498 in the placebo group, corresponding to an incidence rate ratio of 0.99 (95% CI: 0.85, 1.14). We found no statistically significant effect of the intervention on any of the 20 clinical outcomes, including infection incidence and facility visits.

CONCLUSIONS

Our results from a population at risk of vitamin B-12 deficiency and with prevalent childhood infections do not indicate that vitamin B-12 supplementation reduces the burden of common infections. This trial was registered at clinicaltrials.gov as NCT02272842.