Randomized controlled trial of calcium supplementation in healthy, nonosteoporotic, older men.
BACKGROUND
There is no consistent evidence, to our knowledge, that calcium supplementation affects bone mineral density (BMD) in men, despite male osteoporosis being a common clinical problem.


METHODS
To determine the effects of calcium supplementation (600 mg/d, 1200 mg/d, or placebo) on BMD in men, we conducted a double-blind, randomized controlled trial for a 2-year period at an academic clinical research center. A total of 323 healthy men at least 40 years old (mean age, 57 years) were recruited by newspaper advertisement. Complete follow-up was achieved in 96% of subjects.


RESULTS
The BMD increased at all sites in the group receiving calcium, 1200 mg/d, by 1% to 1.5% more than those receiving placebo. The results for the group receiving calcium, 600 mg/d, were not different from the placebo group at any BMD site. There was no interaction between the BMD treatment effect and either age or dietary calcium intake. There were dosage-related, sustained decreases in serum parathyroid hormone (P < .001), total alkaline phosphatase activity (P = .01), and procollagen type 1 N-terminal propeptide (P < .001) amounting to 25%, 8%, and 20%, respectively, in the group receiving calcium, 1200 mg/d, at 2 years. Tooth loss, constipation, and cramps were unaffected by calcium supplementation, falls tended to be less frequent in the group receiving calcium, 1200 mg/d, but vascular events tended to be more common in the groups receiving calcium vs the group receiving placebo.


CONCLUSIONS
Calcium, 1200 mg/d, has effects on BMD in men comparable with those found in postmenopausal women but a dosage of 600 mg/d is ineffective for treating BMD.


BACKGROUND
actr.org.au Identifier: 012605000274673.
Reid
Ian R
IR
Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand. i.reid@auckland.ac.nz
Ames
Ruth
R
Mason
Barbara
B
Reid
Helen E
HE
Bacon
Catherine J
CJ
Bolland
Mark J
MJ
Gamble
Gregory D
GD
Grey
Andrew
A
Horne
Anne
A
D000058:Accidental Falls; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D015519:Bone Density / Q000187:drug effects*; D019355:Calcium Citrate / Q000008:administration & dosage; D002136:Calcium, Dietary / Q000494:pharmacology*; D003248:Constipation; D019587:Dietary Supplements; D004311:Double-Blind Method; D005500:Follow-Up Studies; D050723:Fractures, Bone; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D009120:Muscle Cramp; D010281:Parathyroid Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011347:Procollagen / Q000097:blood; D016388:Tooth Loss; D014652:Vascular Diseases / Q000139:chemically induced
D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide; D000469:Alkaline Phosphatase; D019355:Calcium Citrate