Credits Earned (2024) Crédits obtenus

Redeem Prepaid Membership

Tools for Practice Outils pour la pratique

#41 Does calcium supplementation increase the risk of MI?

Do calcium supplements increase risk of myocardial infarction (MI) and other cardiovascular disease (CVD)?

Evidence suggests that calcium supplementation might slightly increase the risk of MI and perhaps other CVD. Although there are limitations to the evidence and the increased CVD risk is likely <1%, the benefit-to-harm ratio might not favour calcium supplementation.

CFPCLearn Logo

Reading Tools for Practice Article can earn you MainPro+ Credits

La lecture d'articles d'outils de pratique peut vous permettre de gagner des crédits MainPro+

Join Now S’inscrire maintenant

Already a CFPCLearn Member? Log in

Déjà abonné à CMFCApprendre? Ouvrir une session

Five recent systematic reviews had differing conclusions:
  • The first reviewed 15 Randomized Controlled Trials (RCTs) comparing calcium supplementation (≥500 mg/day) vs. placebo.1
    • Only one CVD outcome reached statistical significance:
      • Calcium increased MI risk, Relative Risk 1.27 (1.01-1.59).
      • Absolute risk was <1% and Number Needed to Harm (NNH) for one MI was 135 to 211 over four years.
  • Another examined 17 studies comparing vitamin D, calcium, or both vs. placebo:2
      • No comparisons reached statistical significance.
      • More than 99% of data for calcium and vitamin D vs. placebo were from the Women’s Health Initiative (WHI),3 and 54% of participants were taking extra calcium.4
  • A subgroup (similar to per-protocol) analysis of WHI data5 excluding those taking extra calcium found borderline significant increases in hazard ratios for MI [1.22 (1.00-1.50)] and MI or Stroke [1.16 (1.00-1.35)].
    • Updating the previous meta-analysis1 with this data, calcium (with or without vitamin D) significantly increased:5
      • MI NNH=240 over five years, p=0.004 and,
      • MI or stroke NNH=178 over five years, p=0.009.
  • A systematic review on a variety of calcium-related topics concluded there is no interaction between calcium and CVD risk.6
  • The newest systematic review of 11 RCTs (50,252 participants):7
    • Trends toward harm in odds ratios:
      • CVD [1.16 (0.97-1.68)],
      • MI [1.28 (0.97-1.68)],
      • Stroke [1.14 (0.90-1.46)].
  • Limitations: Over-interpretation of data (including calculating NNH for non-statistically significant outcomes),1 excluded relevant studies,2,7 small sample size,2 no analysis of different outcomes,2 large number of comparisons,5 sub-group analyses,5 possible conflict of interest,5 absolute numbers not reported.7
  • No RCT of calcium supplementation was designed to assess CVD outcomes.1,2
    • These meta-analyses1-3,7 represent post-hoc analyses of secondary or unplanned outcomes, possibly inadequately reported.8
  • Trials of vitamin D alone do not suggest CVD harm.9
  • Calcium (88% with vitamin D) reduces fracture (any type), Number Needed to Treat of 63 over 3.5 years.10
    • Calcium alone just failed to reach statistical significance.
    • Other studies suggest calcium alone does not reduce non-vertebral fracture and might increase hip fracture.11,12

Latest Tools for Practice
Derniers outils pour la pratique

#367 Oral Calcitonin Gene-related Peptide Antagonists: A painfully long name for the acute treatment of migraines

What are the risks and benefits of ubrogepant for the acute treatment of episodic migraines?
Read Lire 0.25 credits available Crédits disponibles

#366 Looking for Closure: Managing simple excisions or wounds efficiently

What are some options for efficiency in wound closure?
Read Lire 0.25 credits available Crédits disponibles

#365 Shrooms for Glooms: Evidence for psilocybin for depression

What are the benefits and harms of psilocybin for treatment-resistant/recurrent depression?
Read Lire 0.25 credits available Crédits disponibles

This content is certified for MainPro+ Credits, log in to access

Ce contenu est certifié pour les crédits MainPro+, Ouvrir une session

  • Christina Korownyk MD CCFP
  • G. Michael Allan MD CCFP

1. Bolland MJ, Avenell A, Baron JA, et al. BMJ. 2010; 341:c3691.

2. Wang L, Manson JE, Song Y, et al. Ann Intern Med. 2010; 152(5):315-23.

3. Hsia J, Heiss G, Ren H, et al. Circulation. 2007; 115(7):846-54.

4. Wactawski-Wende J, Kotchen JM, Anderson GL, et al. N Engl J Med. 2006; 354(7):684-96.

5. Bolland MJ, Grey A, Avenell A, et al. BMJ. 2011; 342:d2040.

6. Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Ross AC, Taylor CL, Yaktine AL, et al., editors. Dietary Reference Intakes for Calcium and Vitamin D. Washington (DC): National Academies Press (US); 2011.

7. Mao PJ, Zhang C, Tang L, et al. Int J Cardiol. 2013; 169:106-11.

8. Bolland MJ, Barber PA, Doughty RN, et al. BMJ. 2008; 336(7638):262-6.

9. Pittas AG, Chung M, Trikalinos T, et al. Ann Intern Med. 2010; 152(5):307-14.

10. Tang BM, Eslick GD, Nowson C, et al. Lancet. 2007; 370(9588):657-66.

11. Bischoff-Ferrari HA, Dawson-Hughes B, Baron JA, et al. Am J Clin Nutr. 2007; 86(6):1780-90.

12. Reid IR, Bolland MJ, Grey A. Osteoporos Int. 2008; 19(8):1119-23.

Authors do not have any conflicts of interest to declare.

Les auteurs n’ont aucun conflit d’intérêts à déclarer.

Most recent review: 17/02/2015

By: Adrienne J Lindblad BSP ACPR PharmD


Evidence Updated: Systematic review added; Bottom Line: Unchanged.

Learning at a glance
Yearly credits
Acquired ()
Your content by topic
Cardiology Dermatology Emergency
My Bookmarks