Calcium + Vitamin D: Surprises From Long-term Follow-up

JoAnn E. Manson, MD, DrPH


December 11, 2013

3 Areas of Support for Supplements

We now have 3 lines of evidence of benefit for calcium plus vitamin D supplementation: the reduction in hip fracture seen among adherent women, the reduction in vertebral fracture in the intention-to-treat analyses, and the improvement or better results for bone mineral density with active treatment compared with placebo and also in the intention-to-treat analyses. Overall, there is increasing evidence that calcium plus vitamin D supplementation does have benefits for bone health.

Also shown in the new report is that with longer-term follow-up, a statistically significant reduction in in situ breast cancer emerged -- a 13% reduction overall. The authors reported no reduction in invasive breast cancer, but it will be of interest to see whether such a reduction does emerge with longer follow-up.

In terms of all cancers, among the women who had low baseline intake of vitamin D, there was a statistically significant 9% reduction in total cancer with supplementation, and also a marginally significant 9% reduction in all-cause mortality. No reduction in colorectal cancer was seen in the trial.

For the cardiovascular endpoints, such as heart disease, stroke, and total cardiovascular events, there was no evidence of benefit or risk. Thus, this was a neutral result for cardiovascular outcomes, which is notable given the controversy about whether calcium may increase the risk for cardiovascular events.

The overall findings appear to be favorable for calcium and vitamin D supplements compared with placebo. We certainly need additional trials of higher-dose vitamin D supplementation beyond 400 IU daily. The Institute of Medicine now recommends that women older than 50 years have at least 1200 mg of calcium per day from a combination of diet and supplements if needed, and 600-800 IU of vitamin D. Perhaps randomized trials of higher-dose vitamin D supplements will show that higher-dose supplementation can provide greater benefits.

Thank you very much for your attention. This is JoAnn Manson.


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