Calcium plus vitamin D supplementation and the risk of postmenopausal weight gain.
BACKGROUND
Obesity in the United States has increased significantly during the past several decades. The role of calcium in the maintenance of a healthy body weight remains controversial.


METHODS
A randomized, double-blinded, placebo-controlled trial was performed with 36 282 postmenopausal women, aged 50 to 79 years, who were already enrolled in the dietary modification and/or hormone therapy arms of the Women's Health Initiative clinical trial. Women were randomized at their first or second annual visit to receive a dose of 1000 mg of elemental calcium plus 400 IU of cholecalciferol (vitamin D) or placebo daily. Change in body weight was ascertained annually for an average of 7 years.


RESULTS
Women receiving calcium plus cholecalciferol supplements vs women receiving placebo had a minimal but consistent favorable difference in weight change (mean difference, -0.13 kg; 95% confidence interval, -0.21 to -0.05; P = .001). After 3 years of follow-up, women with daily calcium intakes less than 1200 mg at baseline who were randomized to supplements were 11% less likely to experience small weight gains (1-3 kg) and 11% less likely to gain more moderate amounts of weight (>3 kg) (P for interaction for baseline calcium intake = .008).


CONCLUSIONS
Calcium plus cholecalciferol supplementation has a small effect on the prevention of weight gain, which was observed primarily in women who reported inadequate calcium intakes.


BACKGROUND
clinicaltrials.gov Identifier: NCT00000611.
Caan
Bette
B
Division of Research, Kaiser Permanente Northern California, Oakland, CA 94612, USA. bjc@dor.kaiser.org
Neuhouser
Marian
M
Aragaki
Aaron
A
Lewis
Cora Beth
CB
Jackson
Rebecca
R
LeBoff
Meryl S
MS
Margolis
Karen L
KL
Powell
Lynda
L
Uwaifo
Gabriel
G
Whitlock
Evelyn
E
Wylie-Rosett
Judy
J
LaCroix
Andrea
A
D000368:Aged; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002762:Cholecalciferol / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology*; D013997:Time Factors; D014815:Vitamins / Q000008:administration & dosage*; D015430:Weight Gain / Q000187:drug effects*
D050071:Bone Density Conservation Agents; D002136:Calcium, Dietary; D014815:Vitamins; D002762:Cholecalciferol