title: Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis.
abstract: BACKGROUND
  Whether calcium supplementation can reduce osteoporotic fractures is uncertain. We did a meta-analysis to include all the randomised trials in which calcium, or calcium in combination with vitamin D, was used to prevent fracture and osteoporotic bone loss.
  
  
  METHODS
  We identified 29 randomised trials (n=63 897) using electronic databases, supplemented by a hand-search of reference lists, review articles, and conference abstracts. All randomised trials that recruited people aged 50 years or older were eligible. The main outcomes were fractures of all types and percentage change of bone-mineral density from baseline. Data were pooled by use of a random-effect model.
  
  
  RESULTS
  In trials that reported fracture as an outcome (17 trials, n=52 625), treatment was associated with a 12% risk reduction in fractures of all types (risk ratio 0.88, 95% CI 0.83-0.95; p=0.0004). In trials that reported bone-mineral density as an outcome (23 trials, n=41 419), the treatment was associated with a reduced rate of bone loss of 0.54% (0.35-0.73; p<0.0001) at the hip and 1.19% (0.76-1.61%; p<0.0001) in the spine. The fracture risk reduction was significantly greater (24%) in trials in which the compliance rate was high (p<0.0001). The treatment effect was better with calcium doses of 1200 mg or more than with doses less than 1200 mg (0.80 vs 0.94; p=0.006), and with vitamin D doses of 800 IU or more than with doses less than 800 IU (0.84 vs 0.87; p=0.03).
  
  
  CONCLUSIONS
  Evidence supports the use of calcium, or calcium in combination with vitamin D supplementation, in the preventive treatment of osteoporosis in people aged 50 years or older. For best therapeutic effect, we recommend minimum doses of 1200 mg of calcium, and 800 IU of vitamin D (for combined calcium plus vitamin D supplementation).
authors.affiliation: Centre for Complementary Medicine Research, University of Western Sydney, New South Wales, Australia. benjamin@clubsalsa.com.au
authors.forename: Benjamin M P
authors.initials: BM
authors.lastname: Tang
authors.forename: Guy D
authors.initials: GD
authors.lastname: Eslick
authors.forename: Caryl
authors.initials: C
authors.lastname: Nowson
authors.forename: Caroline
authors.initials: C
authors.lastname: Smith
authors.forename: Alan
authors.initials: A
authors.lastname: Bensoussan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000187:drug effects; D002118:Calcium / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D005598:Fractures, Spontaneous / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000517:prevention & control*; D010349:Patient Compliance; D012044:Regression Analysis; D012306:Risk; D014807:Vitamin D / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D; D002118:Calcium