title: Effects of calcium supplementation on body weight and blood pressure in normal older women: a randomized controlled trial.
abstract: BACKGROUND
  Epidemiological data suggest that high calcium intakes are associated with decreased body weight and blood pressure. However, there is little evidence from randomized trials that addresses these important issues.
  
  
  OBJECTIVE
  The objective of this study was to assess the long-term effects of calcium on body weight and blood pressure.
  
  
  METHODS
  This is a substudy of an ongoing, double-blind, randomized, controlled trial of calcium supplementation. End points were assessed at 30 months.
  
  
  METHODS
  This study was performed at a university medical center.
  
  
  METHODS
  Normal postmenopausal women (mean age, 74 yr; mean weight, 67 kg; mean blood pressure, 134/70 mm Hg at baseline) participated in this study.
  
  
  METHODS
  Study subjects were treated with calcium (1 g/d; n = 732) and placebo (n = 739).
  
  
  METHODS
  Body weight and blood pressure were the main outcome measures.
  
  
  RESULTS
  Weight decreased by 368 +/- 132 g (mean +/- se) with calcium treatment and by 369 +/- 134 g with placebo (P = 0.93). Fat and lean masses did not show an effect of calcium. Blood pressure showed transient reductions of 1-2 mm Hg at 6 months in the calcium group, resulting in a significant between-group difference only for systolic pressure (P = 0.048). At 30 months, the change from baseline in systolic pressure was 0.0 +/- 0.9 mm Hg in the calcium group and 2.4 +/- 0.9 mm Hg in the placebo group (P = 0.14). For diastolic pressures, the changes were -0.2 +/- 0.4 and 0.8 +/- 0.4 mm Hg, respectively (P = 0.13). In those with baseline calcium intakes less than 600 mg/d, the treatment effect was greater and did persist.
  
  
  CONCLUSIONS
  Calcium supplementation of 1 g/d does not produce biologically significant effects on body weight, and its hypotensive effect is small and transient in most women.
authors.affiliation: Department of Medicine, University of Auckland, Private Bag 92019, Auckland 1020, New Zealand. i.reid@auckland.ac.nz
authors.forename: Ian R
authors.initials: IR
authors.lastname: Reid
authors.forename: Anne
authors.initials: A
authors.lastname: Horne
authors.forename: Barbara
authors.initials: B
authors.lastname: Mason
authors.forename: Ruth
authors.initials: R
authors.lastname: Ames
authors.forename: Usha
authors.initials: U
authors.lastname: Bava
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Gamble
mesh_terms: D000368:Aged; D001794:Blood Pressure; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002136:Calcium, Dietary / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged
chemical_list: D002136:Calcium, Dietary