Carolyn J. Crandall, MD, MS; Jane A. Cauley, DrPH
In postmenopausal women, how does supplementation with calcium plus vitamin D affect cardiovascular (CV) risk in users and nonusers of personal, nonprotocol calcium supplements?
Subgroup analysis of a randomized placebo-controlled trial (Women’s Health Initiative [WHI] Calcium/Vitamin D Supplementation [CaD] study) using a limited access dataset. Analyses were prespecified before access to data was provided.
{Concealed}*.†
Blinded (participants, {clinicians, data collectors, outcome assessors, and data monitoring committee}*).†
{Mean 7 years}‡.
{40 clinical centers in the USA}‡.
36 282 community-dwelling, postmenopausal women {50 to 79 years of age}‡ (mean age 63 y at WHI CaD study randomization). 54% were taking personal calcium supplements at randomization; users and nonusers of supplements differed on several baseline variables.
Calcium, 1 g/d, plus vitamin D, 400 IU/d (n = 18 176), or placebo (n = 18 106). {Personal, nonprotocol use of calcium ≤ 1000 mg/d and vitamin D ≤ 1000 IU/d was allowed}‡.
Myocardial infarction (MI), stroke, coronary revascularization (percutaneous coronary intervention or coronary artery bypass graft), and composites of the individual endpoints with or without death due to coronary heart disease.
{97%}‡ ({intention-to-treat analysis}*).
The main results for individual endpoints are shown in the Table. Calcium plus vitamin D was associated with a borderline significant increase in risk for the composite of clinical MI or stroke in nonusers but not in users of personal calcium (P = 0.006 for interaction) (Table); there was no interaction between treatment and personal calcium use for other composite endpoints.
In postmenopausal women, supplementation with calcium and vitamin D was associated with increased risk for some cardiovascular outcomes in nonusers of personal calcium supplements.
Calcium plus vitamin D supplementation vs placebo in postmenopausal women§
§MI = myocardial infarction; other abbreviations defined in Glossary. Hazard ratio < 1 indicates benefit for calcium plus vitamin D.
||Includes clinical and silent MIs.
Crandall CJ, Cauley JA. Calcium plus vitamin D was associated with increased cardiovascular risk in women not taking personal calcium supplements. Ann Intern Med. ;155:JC2–3. doi: 10.7326/0003-4819-155-4-201108160-02003
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© 2019
Published: Ann Intern Med. 2011;155(4):JC2-3.
DOI: 10.7326/0003-4819-155-4-201108160-02003
Cardiology, Coronary Risk Factors, Prevention/Screening.