Published: 12 December 2013

Do Calcium Supplements Increase Cardiovascular Risk?

Prescriber Update 34(4): 40
December 2013

Key Messages

  • The available evidence does not support an association between the use of calcium supplements and adverse cardiovascular events.
  • The absence of evidence for cardiovascular risk does not negate the requirement for appropriate prescribing of calcium supplements.

The Medicines Adverse Reactions Committee (MARC) recently reviewed data on the risk of adverse cardiovascular outcomes associated with the use of calcium supplements. The MARC concluded that there is insufficient evidence to support an association at this time.

At the September 2013 MARC meeting, data were reviewed from recent meta-analyses and reanalyses of randomised controlled trials that reported cardiovascular events. This review identified contradictory outcomes in relation to the risk of cardiovascular events in patients taking calcium supplements. These differences included different outcomes when the same dataset was analysed by different groups1,2.

One group identified an increased risk of myocardial infarction associated with calcium supplements but no increase of all-cause death in a meta-analysis1. However, another group’s meta-analysis analysing similar data did not identify an increased risk3.

Another analysis of a randomised controlled trial found that calcium supplements were protective in those individuals with pre-existing cardiovascular disease4.

There were limitations to all the analyses reviewed. These limitations included an absence of cardiovascular events as primary outcomes, patient data were not always gathered in a standardised manner and there was a lack of information regarding dietary calcium intake. There were differences in the trials analysed with respect to the patient population. Adherence was also a factor in the trials with some trials reporting adherence as low as 50%.

The Centre for Adverse Reactions Monitoring (CARM) has received nine reports of suspected adverse reactions involving calcium supplements since 2008. Only one report involved a cardiovascular event of arrhythmia in a patient also taking clozapine.

The minutes of the September 2013 MARC meeting are available on the Medsafe website ( Medsafe will continue to monitor this issue as it does for all medicines.

  1. Bolland MJ, Grey A, Avenell A, et al. 2011. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women's Health Initiative limited access dataset and meta-analysis. BMJ 342: d2040.
  2. Prentice RL, Pettinger MB, Jackson RD, et al. 2013. Health risks and benefits from calcium and vitamin D supplementation: Women's Health Initiative clinical trial and cohort study. Osteoporosis International 24(2): 567–580.
  3. Wang L, Manson JE, Sesso HD. 2012. Calcium intake and risk of cardiovascular disease: a review of prospective studies and randomized clinical trials. American Journal of Cardiovascular Drugs 12(2): 105–116.
  4. Lewis JR, Calver J, Zhu K, et al. 2011. Calcium supplementation and the risks of atherosclerotic vascular disease in older women: results of a 5-year RCT and a 4.5-year follow-up. Journal of Bone and Mineral Research 26(1): 35–41.