Best of 2024: Mixed Long-term Effects of Calcium and Vitamin D in Postmenopausal Women Save

This article originally appeared March 11, 2024, and is being shared again as a "Best of 2024". Enjoy!

A follow-up analysis of a randomized clinical trial found that the use of calcium and vitamin D supplements among postmenopausal women was associated with decreased risk for cancer mortality, but increased risk for cardiovascular disease (CVD) mortality. The analysis is published in Annals of Internal Medicine.

A multicenter US trial of 36 282 postmenopausal women randomized 1:1 to either 1000 mg of calcium carbonate (400 mg of elemental calcium) with 400 IU of vitamin D3 daily (CaD group) or placebo. This study was a post hoc analysis of long-term (7-year) followup data and examined rates of colorectal, invasive breast, and total cancer; disease-specific and all-cause mortality; total cardiovascular disease (CVD); and hip fracture.

Compared to placebo, those treated with CaD experienced:

• 7% decrease in cancer mortality (HR 0.93; 95% CI, 0.87 to 0.99)
• 6% increase in CVD mortality (HR 1.06; 1.01 to 1.12)
• No effect on all-cause mortality (HR, 1.00)

Hip fracture and CVD outcomes were available on only a subset of participants, and effects of calcium versus vitamin D versus joint supplementation could not be disentangled.