title: Randomized controlled trial of calcium supplementation in healthy, nonosteoporotic, older men.
abstract: 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.
authors.affiliation: Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand. i.reid@auckland.ac.nz
authors.forename: Ian R
authors.initials: IR
authors.lastname: Reid
authors.forename: Ruth
authors.initials: R
authors.lastname: Ames
authors.forename: Barbara
authors.initials: B
authors.lastname: Mason
authors.forename: Helen E
authors.initials: HE
authors.lastname: Reid
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Bacon
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Bolland
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Gamble
authors.forename: Andrew
authors.initials: A
authors.lastname: Grey
authors.forename: Anne
authors.initials: A
authors.lastname: Horne
mesh_terms: 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
chemical_list: D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide; D000469:Alkaline Phosphatase; D019355:Calcium Citrate