Vitamin D receptor gene polymorphisms modulate the skeletal response to vitamin D supplementation in healthy girls.
OBJECTIVE
Vitamin D receptor (VDR) gene plays an important role in bone mass regulation. We have previously shown a beneficial effect of vitamin D supplementation on bone mass in girls. This study investigated whether the musculo-skeletal response to Vitamin D was modulated by polymorphisms in VDR gene.


METHODS
Randomized placebo-controlled trial.


METHODS
179 girls (10-17 years), were randomly assigned to placebo or Vitamin D3 for one year. VDR genotypes were determined in 167 girls using BsmI, TaqI and ApaI restriction enzymes. Bone mass at the spine, hip, forearm and total body, and lean mass were measured by DXA at baseline and at one year.


RESULTS
After one year, VDR gene polymorphisms using Bsm1 and TaqI restriction enzymes were associated with percent changes in bone area, BMC and BMD at multiple skeletal sites in the Vitamin D3 group but not in the placebo group. The least increments were observed in the BB and tt genotypes. No similar effect was observed with ApaI enzyme. This relationship between VDR genotypes and changes in BMD and BMC remained significant after adjustment for puberty, changes in lean mass, height and bone area.


CONCLUSIONS
VDR gene polymorphisms influence the skeletal response to vitamin D supplementation in healthy adolescent girls.
Arabi
Asma
A
Calcium Metabolism and Osteoporosis Program, American University of Beirut, Beirut, Lebanon. aa22@aub.edu.lb
Zahed
Laila
L
Mahfoud
Ziyad
Z
El-Onsi
Lina
L
Nabulsi
Mona
M
Maalouf
Joyce
J
Fuleihan
Ghada El-Hajj
Gel-H
D000293:Adolescent; D000886:Anthropometry; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology*; D002648:Child; D002762:Cholecalciferol / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D005838:Genotype; D006262:Health; D006801:Humans; D015999:Multivariate Analysis; D010919:Placebos; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D018167:Receptors, Calcitriol / Q000235:genetics*
D010919:Placebos; D018167:Receptors, Calcitriol; D002762:Cholecalciferol