Calcium/vitamin D supplementation and coronary artery calcification in the Women's Health Initiative.
OBJECTIVE
Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events. The relationship between calcium plus vitamin D (calcium/D) supplementation and coronary artery calcium (CAC) has not been previously assessed in a randomized trial setting. We compared CAC scores after trial completion between women randomized to calcium/vitamin D supplementation and women randomized to placebo.


METHODS
In an ancillary substudy of women randomized to calcium carbonate (1,000 mg of elemental calcium daily) plus vitamin D3 (400 IU daily) or placebo, nested within the Women's Health Initiative trial of estrogen among women who underwent hysterectomy, we measured CAC with cardiac CT in 754 women aged 50 to 59 years at randomization. Imaging for CAC was performed at 28 of 40 centers after a mean of 7 years of treatment, and scans were read centrally. CAC scores were measured by a central reading center with masking to randomization assignments.


RESULTS
Posttrial CAC measurements were similar in women randomized to calcium/D supplementation and those receiving placebo. The mean CAC score was 91.6 for women receiving calcium/D and 100.5 for women receiving placebo (rank test P value = 0.74). After adjustment for coronary risk factors, multivariate odds ratios for increasing CAC score cutpoints (CAC >0, > or =10, and > or =100) for calcium/D versus placebo were 0.92 (95% CI, 0.64-1.34), 1.29 (0.88-1.87), and 0.90 (0.56-1.44), respectively. Corresponding odds ratios among women with a 50% or higher adherence to study pills and for higher levels of CAC (>300) were similar.


CONCLUSIONS
Treatment with moderate doses of calcium plus vitamin D3 did not seem to alter coronary artery calcified plaque burden among postmenopausal women. Whether higher or lower doses would affect this outcome remains uncertain.
Manson
JoAnn E
JE
Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. jmanson@rics.bwh.harvard.edu
Allison
Matthew A
MA
Carr
J Jeffrey
JJ
Langer
Robert D
RD
Cochrane
Barbara B
BB
Hendrix
Susan L
SL
Hsia
Judith
J
Hunt
Julie R
JR
Lewis
Cora E
CE
Margolis
Karen L
KL
Robinson
Jennifer G
JG
Rodabough
Rebecca J
RJ
Thomas
Asha M
AM
D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002119:Calcium Carbonate / Q000008:administration & dosage*; D002762:Cholecalciferol / Q000008:administration & dosage*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D014057:Tomography, X-Ray Computed
D050071:Bone Density Conservation Agents; D002762:Cholecalciferol; D002119:Calcium Carbonate