Hypovitaminosis D in infants: Evidence that increased intake of vitamin D reduces the incidence of allergic and respiratory disorders.

Aim: The study assessed the relationship between vitamin D status in infants and the presence of allergic and/or respiratory disorders.

Materials and methods: The study cohort comprised 81 hospitalized infants presenting at the Pediatric Clinic, University Clinical Center Kragujevac, Serbia, between January 2011 and June 2016.

Results: The age of the infants ranged from 29 days to 12 months. All infants received prophylactic doses of vitamin D3 of 400 IU/daily until the end of the first year of life regardless of whether they are fed with adapted infant formula (n = 20) or breast milk (n = 37) or concurrently both (n = 24), up to the 5^th month of life. The mean level of plasma 25(OH)D was 29.65 ng/mL. Hypovitaminosis D (mean serum level of 25(OH)D < 30 ng/mL) was found in n = 38 infants of which 6 presented with severe vitamin D deficiency (level below 10 ng/mL), 13 presented with vitamin D deficiency (level between 10 and 20 ng/mL) and 19 had vitamin D insufficiency (levels between 20 and 30 ng/mL). The median vitamin D serum level in infants with allergic disease (n = 16) was 32.35 ng/mL and in infants with respiratory disease (n = 65) 28.99 ng/mL.

Conclusion: Daily vitamin D3 supplementation with 400 IU in infants until the end of the first year of life is too low to provide optimal defense against respiratory and/or allergic conditions.