Do calcium plus vitamin D supplements increase cardiovascular risk?

Calcium supplements are widely used in the prevention of osteoporosis and as an adjunct to specific osteoporosis treatment but have been associated with a possible increase in the risk of adverse cardiovascular outcomes.1 In the linked study (doi:10.1136/bmj.d2040),2 Bolland and colleagues investigate the effects of personal use of calcium supplements on cardiovascular risk in the Women’s Health Initiative Calcium/Vitamin D (WHI CaD) study and update their meta-analysis of calcium supplements and cardiovascular risk.3 This new analysis is particularly relevant because it includes calcium supplements given with vitamin D.

The meta-analysis extends one previously undertaken by the same group in which calcium supplementation was associated with a significantly increased risk of stroke and myocardial infarction.1 That study was followed by a lively debate on the BMJ website and elsewhere, when it was criticised for reporting individual outcomes when the global end point was not significant, for counting events rather than people with events, and for building on studies that were not designed for cardiovascular outcomes and adjudicated accordingly.

In the …