Vitamin B12, derived from animal food products, is vital for neurological function and infant development. The aim of my dissertation was to explore infant vitamin B12 deficiency in a Norwegian population, including its frequency and clinical relevance, risk factors, presenting symptoms, and whether newborn screening could have detected it.

We performed a retrospective study with 85 infant cases diagnosed with B12 deficiency and one prospective, observational study with 252 healthy infants who were also controls for the cases, in addition to 850 newborn screening dried blood spot controls.

Ten percent of presumed healthy infants had tHcy>8 µmol/l and tremor or excessive sleep, suggesting infant B12 deficiency. B12 deficiency often presented with severe symptoms like spells of apneas and seizures in infant cases. None of their mothers were vegans or vegetarians. The combination of nitrous oxide and exclusive breastfeeding was associated with an earlier presentation of infant B12 deficiency. We suggest nitrous oxide during labor as a novel risk factor for infant B12 deficiency. Newborn screening failed to identify ≥90% of infants diagnosed with symptomatic B12 deficiency after the newborn period. 

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CHALLENGES OF SETTING NUTRIENT REFERENCE VALUES AND CUT-OFFS FOR DEFINING DEFICIENCIES AND EXCESS IN PEDIATRIC POPULATIONS

Dissertation was on 22/4 2024

Vitamin B12-mangel hos spedbarn i Veileder i pediatri

Publications in my dissertation

The prevalence and clinical relevance of hyperhomocysteinemia suggesting vitamin B12 deficiency in presumed healthy infants

Breastfed Infants With Spells, Tremor, or Irritability: Rule Out Vitamin B12 Deficiency

Nitrous oxide in labour predicted newborn screening total homocysteine and is a potential risk factor for infant vitamin B12 deficiency

A Retrospective Evaluation of the Predictive Value of Newborn Screening for Vitamin B12 Deficiency in Symptomatic Infants Below 1 Year of Age