Vitamin D in Preterm and Full-Term Infants

Abstract

Vitamin D is necessary for the active (transcellular) absorption of calcium and for skeletal health. Inadequate vitamin D in infants leads to increased risks of poor bone mineralization and ultimately rickets. Rickets is uncommon in full-term infants with a much higher risk in very premature infants. However, the primary cause of rickets in premature infants is a deficiency of calcium and phosphorus, not vitamin D. Available research, as well as most guidelines, recommend an intake of 400 IU daily of vitamin D as adequate for bone health in preterm and full-term infants. Higher doses have not been consistently shown to have specific clinical benefits for healthy infants. There are no strong data to support either routine testing of serum 25-hydroxyvitamin D or targeting high serum 25-hydroxyvitamin D levels (e.g., 30 ng/mL) in healthy preterm or full-term infants. Vitamin D is commonly provided to infants via drops for breastfed babies or via infant formula, although alternative dosing approaches exist for breastfed infants, which some families may prefer. These include the use of drops placed on the mother’s breast, dissolvable doses, and high maternal doses (approximately 6,400 IU daily). Infant formula contains vitamin D, and most infants will reach an intake from formula of about 400 IU daily within the first 2 months of life if they are consuming routine cow milk-based formula. Although vitamin D toxicity is very uncommon, caution should be used to avoid extremely concentrated high doses found in some commercially available drops. Infants with liver or kidney disease may need special attention to vitamin D intake and status. Further research is needed to define the role of vitamin D in non-bone health outcomes of infants and to identify methods to enhance compliance with current recommendations for vitamin D intake in infants.

Monitored Supplementation of Vitamin D in Preterm Infants: A Randomized Controlled Trial

“…Notably, our observation period for the potential overdosing period was longer than other studies. This is consistent with Abrams' latest review, in which the author suggests that potential toxic levels of vitamin D may present in later infanthood (10). In contrast, Monangi et al 36 ] evaluated low-dose supplementation in 120 preterm infants born <32 weeks of GA at 36 weeks of PMA or at discharge.…”

“…Eighty percent of calcium and phosphorus placental transfer occurs between 24-40 weeks of gestation; hence, preterm infants are especially prone to adverse effects of VDD, including MBD and low bone mineral status 23,[30][31] ]. However, high-dose supplementation without monitoring can lead to overdosing despite the lack of consensus in vitamin D toxicity threshold (100 or 150 ng/mL) [10][11]29 ]. Some experts suggest lower levels, such as 75-80 ng/mL 11,15 ], due to the increased risk of hypercalcemia in preterm infants 15,32 ].…”

“…In the premature infants' population, VDD can lead to bone disease, which is described as rickets of prematurity, osteopenia of prematurity, or metabolic bone disease (MBD) 9 ]. Nevertheless, high vitamin D supplementation among low-birth-weight infants with immature renal filtration can lead to vitamin D toxicity with hypercalcemia or hypercalciuria and cause serious illness [10][11] ].…”

“…Vitamin D dosage, safety, and effectiveness in preterm infants remain controversial and clear criteria for adequate supplementations have not been established. Some experts have suggested a new approach to vitamin D supplementation-monitored therapy 8,10,[14][15] ]. However, this approach's clinical significance and long-term effect have not been studied in most preterm populations.…”

Overview of Important Micronutrients Supplementation in Preterm Infants after Discharge: A Call for Consensus

“…The majority (>90%) of vitamin D is synthesized by skin exposition to sunlight, whereas the intake from diet is less significative. Although vitamin D synthesis from sunlight exposure is highly effective, the sunlight hours are reduced during the cold season, thus impairing the vitamin D production [ 60 ]. Moreover, the American Academy of Pediatrics (AAP) does not recommend to expose children less than six months of age directly to the sunlight without proper clothing, reducing sunlight exposure and vitamin D synthesis [ 61 ].…”