Vitamin D nutritional status in preterm infants and response to supplementation.

Little is known about vitamin D status in preterm infants and their response to supplementation. To investigate this, we assessed serum 25-hydroxyvitamin D (25OHD) levels using RIA in a consecutive sample of stable preterm very low birth weight (VLBW) infants (born ≤ 32 weeks gestation or birth weight ≤ 1·5 kg), and we explored associated factors. Serum 25OHD level was first assessed once infants were tolerating feeds ( n 274). If this first 25OHD level was below 50 nmol/l (20 ng/ml), which is the level associated with covering requirements in terms of skeletal health in the majority, then we recommended prolonged augmented vitamin D intake ( ≥ 10 μg (400 IU) daily) from a combination of fortified feeds and vitamin supplements and follow-up re-assessment at approximately 6 weeks corrected age ( n 148). The first assessment, conducted at a median for chronological age of 18 (interquartile range (IQR) 11–28) d, found that 78 % had serum 25OHD levels below 50 nmol/l. Multivariable analysis demonstrated that the determinants of serum 25OHD levels were duration of vitamin D supplementation and gestational age at birth ( r 2 0·215; P 125 nmol/l, a level associated with potential risk of harm. We conclude that low 25OHD levels are an issue for preterm VLBW infants, warranting early nutritional intervention. In infants with serum 25OHD levels