Randomised controlled trial of vitamin D supplementation on bone density and biochemical indices in preterm infants.
OBJECTIVE
To test the hypothesis that a vitamin D dose of 200 IU/kg, maximum 400 IU/day, given to preterm infants will maintain normal vitamin D status and will result in as high a bone mineral density as that attained with the recommended dose of 960 IU/day.


METHODS
Thirty nine infants of fewer than 33 weeks of gestational age were randomly allocated to receive vitamin D 200 IU/kg of body weight/day up to a maximum of 400 IU/day or 960 IU/day until 3 months old. Vitamin D metabolites, bone mineral content and density were determined by dual energy x-ray absorptiometry, and plasma ionised calcium, plasma alkaline phosphatase, and intact parahormone measurements were used to evaluate outcomes.


RESULTS
The 25 hydroxy vitamin D concentrations tended to be higher in infants receiving 960 IU/day, but the differences did not reach significance at any age. There was no difference between the infants receiving low or high vitamin D dose in bone mineral content nor in bone mineral density at 3 and 6 months corrected age, even after taking potential risk factors into account.


CONCLUSIONS
A vitamin D dose of 200 IU/kg of body weight/day up to a maximum of 400 IU/day maintains normal vitamin D status and as good a bone mineral accretion as the previously recommended higher dose of 960 IU/day. Vitamin D is a potent hormone which affects organs other than bone and should not be given in excess to preterm infants.
Backström
M C
MC
Department of Paediatrics, Tampere University Hospital, Tampere, Finland. maria.backstrom@pp.qnet.fi
Mäki
R
R
Kuusela
A L
AL
Sievänen
H
H
Koivisto
A M
AM
Ikonen
R S
RS
Kouri
T
T
Mäki
M
M
D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D015502:Absorptiometry, Photon; D015519:Bone Density / Q000187:drug effects*; D019587:Dietary Supplements; D004334:Drug Administration Schedule; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood; D014807:Vitamin D / Q000008:administration & dosage*
D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2