Calcium/Vitamin D-related CV Events

Based on Poster 1163

“Risk of Cardiovascular Events with Calcium/Vitamin D –

a Re-Analysis of the Women’s Health Initiative”

Mark Bolland, Andrew Grey, Gregory Gamble, Ian Reid

Monday, October 18, 2010

ASBMR 2010

Toronto, Ontario

Background

• A consistent pattern of increased myocardial infarction (MI) risk from calcium supplementation

vs. placebo was demonstrated in a meta-analysis of 11,900 subjects (Bolland et al. IOF 2010,

Abstract OC25)

• Reid et al. re-analyzed the interaction between BMI and the calcium/vitamin D intervention in

the Women’s Health Initiative (WHI)

• As part of the WHI, postmenopausal women received 1 g calcium plus

400 IU vitamin D or placebo and were followed for 7 years

• At baseline, 54% (20,000) of the cohort were already taking personal calcium supplements and

approximately 16,000 women were not

• For non-obese women (BMI<30 kg/m2) randomized to calcium/vitamin D,

there was a significant increased risk for:

– A revascularization procedure (28%)

– Total MI, coronary heart disease, death and revascularization (24%)

Results

• In women not taking personal calcium supplements at baseline, a significant increase in MI and combined stroke/MI was observed

• In women taking personal calcium supplements at baseline, there was no evidence of altered cardiovascular disease (CVD) events

• The addition of vitamin D therefore did not abrogate the effect of calcium on CVD end points except in obese women

Other Studies on Calcium/Vitamin D

and Vascular Events

• In a meta-analysis of 3 such studies, the HR was similar to that identified in the

WHI where the combination of calcium/vitamin D increased the risk of MI by

21% and stroke by 20%

• Given the similarity of the CVD risk between calcium alone and calcium + vitamin D, it is

reasonable to hypothesize that the addition of vitamin D to calcium does not make a

substantive difference to CVD risk

Meta-analysis of Calcium ± Vitamin D Effect on Stroke

Based on the meta-analysis, a 15% increase in the combination of MI and stroke is associated with calcium supplementation with or without vitamin D

Summary

According to these data, if 1000 people were treated with calcium for 5 years

(± Vitamin D), this would result in an estimated increase of:

MIs = 4x

Stroke = 4x

Deaths = 2x

 

At the same time, 3 fractures would be prevented.

Findings suggest that reassessment of the role of calcium supplementation

± vitamin D in osteoporosis prevention and treatment is warranted