Cholecalciferol supplementation throughout winter does not affect markers of bone turnover in healthy young and elderly adults.
Although there have been several studies of the effect of vitamin D status on bone turnover in the elderly, the findings are unclear, and, furthermore, to date very few have investigated this in young adults. The objective of these randomized, placebo-controlled, double-blind, 2-center intervention studies was to investigate the effect of cholecalciferol supplementation (0, 5, 10, and 15 microg cholecalciferol/d) throughout winter time on indices of vitamin D status and bone turnover in young (aged 20-40 y; n = 215) and elderly (aged > or = 64 y; n = 204) adults, with relatively high mean calcium intakes of 976 and 874 mg/d, respectively. Fasting serum concentrations of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), osteocalcin, bone-specific alkaline phosphatase, and carboxyterminal collagen crosslinks were measured by enzyme immunoassays at baseline and endpoint. Fok I and Taq I vitamin D receptor (VDR) genotypes were determined by real-time PCR. Endpoint serum 25(OH)D increased (P < 0.0001) in a dose-related manner with increasing supplemental cholecalciferol (up to 15 microg/d) in 20-40-y olds and up to 10 microg/d in > or = 64-y olds. Endpoint serum PTH was lower (P < 0.05) in the 3 cholecalciferol-supplemented groups compared with that in the placebo group in > or = 64-y olds, but cholecalciferol supplementation did not affect other markers in either cohort and there was no significant interaction with VDR genotype. In conclusion, cholecalciferol supplementation alone throughout winter did not affect bone turnover markers in apparently healthy young and elderly adults, even when stratified by VDR genotype.
Seamans
Kelly M
KM
Department of Food and Nutritional Sciences, University College, Cork, Ireland.
Hill
Tom R
TR
Wallace
Julie M W
JM
Horigan
Geraldine
G
Lucey
Alice J
AJ
Barnes
Maria S
MS
Taylor
Nicola
N
Bonham
Maxine P
MP
Muldowney
Siobhan
S
Duffy
Emeir M
EM
Strain
J J
JJ
Kiely
Mairead
M
Cashman
Kevin D
KD
D000328:Adult; D000368:Aged; D015415:Biomarkers; D001842:Bone and Bones / Q000378:metabolism*; D002762:Cholecalciferol / Q000494:pharmacology*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D055815:Young Adult
D015415:Biomarkers; D002762:Cholecalciferol