• osteocalcin;
  • preterm;
  • urinary deoxypyridinoline;
  • vitamin D


Background: Metabolic bone disease of prematurity is a common problem in preterm infants. The aim of the present paper was to measure the effect of vitamin D, in order to see the relation between vitamin D and urinary excretion of deoxypyridinoline (DPD), serum osteocalcin (OC), calcium (Ca), inorganic phosphorus (P), and alkaline phosphatase (ALP).

Methods: Three different doses of vitamin D, 200 IU/kg (group 1, 11 infants), 400 IU/kg (group 2, 15 infants) and 800 IU/kg bodyweight/day (group 3, 11 infants), were administered to a total of 37 preterm infants between 15th day of birth until the 30th day of birth.

Results: There were no significant differences in levels of serum Ca and P before and after vitamin D supplementation in all groups. Serum ALP levels were increased in all but significantly only in groups 1 and 3. Serum OC levels were also increased in each group by the treatment. Urinary DPD excretion was increased gradually by the increase in vitamin D intake, but it was significant only in group 3.

Conclusion: High dose of vitamin D supplementation might accelerate bone turnover and increased urinary DPD levels might reflect increased bone resorption. To the best of the authors’ knowledge this is the first study comparing the effects of different vitamin D dose, by the means of urinary collagen cross-links, on bone turnover in preterm infants.