Question 2: Vitamin D intake for preterm infants: how much do they really need?

A preterm baby girl born at 25 weeks gestation was evaluated for discharge home. The Senior House Officer was asked to prescribe vitamins and iron. He questioned the local guideline and found there were no international consensus guidelines for vitamin D supplementation in preterm infants on discharge. How much of vitamin D intake (Intervention) given to preterm infants (patient), would maintain vitamin D adequacy, ≥50 nmol/L (≥20 ng/mL) (outcome)? ### Primary sources MEDLINE was searched via PubMed from 1980 to March 2017. The advanced search mode was used with the terms ‘vitamin D’ and ‘preterm infants’ and ‘supplementation’. ### Secondary sources A search of the Cochrane Library using the search terms ‘vitamin D’ and ‘Infants’ were used. Preterm infants are at increased risk of nutritional deficiency including vitamin D insufficiency. The vitamin D status of preterm infants at birth are entirely dependent on maternal vitamin D status, and due to the high prevalence of vitamin D deficiency in pregnancy1 and problems of feeding intolerance, the prevalence of hypovitaminosis D in preterm infants is exacerbated. Vitamin D2 (ergocalciferol) is derived mainly from plants, while vitamin D3 (cholecalciferol) is from animal sources or through the conversion of 7-dehydrocholesterol in the skin by ultraviolet B radiation and this accounts for the main source of vitamin D. Of note, vitamin D2 is less potent and has a shorter duration of action compared with vitamin D3.2 Dietary sources from …