The heart of the matterBMJ 2010; 341 doi: http://dx.doi.org/10.1136/bmj.c4993 (Published 15 September 2010) Cite this as: BMJ 2010;341:c4993
- Bess Dawson-Hughes, professor of medicine1
In their meta-analysis Bolland and colleagues conclude: “Calcium supplements without vitamin D are associated with an increased risk of myocardial infarction.”1 This conclusion relies heavily on unpublished data from the RECORD trial, the source of over half of the cardiovascular disease events in the meta-analysis.
In this trial, investigators posted calcium, vitamin D, their combination, or placebo tablets to participants and asked them to return completed health questionnaires every four months.2 Myocardial infarctions were not an end point of the trial and were not verified. We don’t know the number or the clinical characteristics of participants who did and didn’t return completed questionnaires. The pill compliance rate at two years was only 54.5%, and lower (by 9.4%) in the calcium arms. These factors could introduce bias into group comparisons of myocardial infarctions.
In a recent systematic review Wang et al concluded that calcium supplements have minimal cardiovascular effects and that vitamin D at moderate to high doses either alone or in combination with calcium may reduce cardiovascular risk.3 They did not include the RECORD trial because the cardiovascular data were unpublished.
The relevance of any putative effect of calcium alone on cardiovascular disease might be questioned because calcium alone is no longer recommended to prevent or treat osteoporosis. The broad consensus is that older adults should receive at least 800 IU vitamin D daily to reduce the risk of falls and fractures.4 Thus, there should be few occasions when calcium alone might be recommended. Use of supplements when needed to bring calcium intake up to recommended values need not raise concern on the basis of current evidence.
Cite this as: BMJ 2010;341:c4993
Competing interests: None declared.