Calcium and vitamin d supplementation in postmenopausal women.
BACKGROUND
Bone health is influenced by the intake of both calcium and vitamin D.


OBJECTIVE
Our objective was to evaluate the influence of calcium and vitamin D supplementation on PTH and bone turnover. SETTING, PATIENTS, AND DESIGN: At an ambulatory research center, 159 postmenopausal healthy white women participated in this double-blind, placebo-controlled parallel, longitudinal factorial study that was 6 months in duration.


METHODS
Subjects were randomly allocated to 4 groups: 1) double placebo, 2) calcium (1200 mg daily) plus placebo, 3) vitamin D3 (100 μg) plus placebo, and 4) vitamin D3 and calcium. Serum and urine were collected fasting and 2 hours after a calcium load at baseline and at 3 and 6 months.


METHODS
Serum PTH, cross-linked C-telopeptide (CTX), and procollagen type I N-terminal propeptide (P1NP) were measured.


RESULTS
Before study medication, a calcium load resulted in a decline in PTH and CTX and an increase in urinary calcium excretion. Serum CTX and P1NP declined over time with calcium supplementation but did not change with increased vitamin D intake. There was a decline in PTH in the vitamin D groups in the fasting state compared with placebo. Suppression of PTH was greater after a calcium load in the vitamin D groups. A calcium load decreased PTH and CTX and raised urinary calcium.


CONCLUSIONS
Fasting PTH declines with vitamin D supplementation. PTH declines after calcium intake. Supplementation of the diet with 1200 mg calcium/d reduces bone turnover markers, whereas supplementation with up to100 μg vitamin D3/d does not.
MD, Winthrop University Hospital, 222 Station Plaza North, Suite 510, Mineola, New York 11501. jaloia@winthrop.org.
John F
JF
Aloia
Ruban
R
Dhaliwal
Albert
A
Shieh
Mageda
M
Mikhail
Shahidul
S
Islam
James K
JK
Yeh
D000368:Aged; D016723:Bone Remodeling / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000652:urine; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000009:adverse effects; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000009:adverse effects; D024042:Collagen Type I / Q000097:blood; D019587:Dietary Supplements; D005260:Female; D050723:Fractures, Bone / Q000517:prevention & control; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D010018:Osteomalacia / Q000517:prevention & control; D010024:Osteoporosis / Q000517:prevention & control*; D010281:Parathyroid Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides / Q000097:blood; D010919:Placebos; D017698:Postmenopause / Q000187:drug effects*; D011347:Procollagen / Q000097:blood; D014815:Vitamins / Q000008:administration & dosage / Q000009:adverse effects
D002136:Calcium, Dietary; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D010455:Peptides; D010919:Placebos; D011347:Procollagen; D014815:Vitamins; C052929:collagen type I trimeric cross-linked peptide; C042813:procollagen type I carboxy terminal peptide; D002762:Cholecalciferol; D002118:Calcium