Study urges caution with calcium supplements for patients with heart disease

For the first time, researchers have examined the link between calcium supplementation and the recurrence of cardiovascular events in people with a history of cardiovascular disease (CVD).Conducted in Hong Kong, this large retrospective cohort study included individuals aged 40 and older, all of whom had previously been diagnosed with CVD. It comprised two groups of 17,720 patients: those prescribed calcium supplements constituted the treatment group, while those who never received calcium supplements constituted the control group.Significant increase in risk of recurrenceThe results, published in the Journal of the American Heart Association in April 2026, reveal that, in people with a history of CVD, prescribing calcium supplements is associated with an increased risk of recurrent cardiovascular events (HR, 1.10 [95% CI, 1.07–1.14]), as well as hospitalization or emergency room visits for CVD (HR, 1.16 [95% CI, 1.13–1.20]).“The link between calcium supplementation and recurrent cardiovascular events seems plausible, as circulating calcium plays an important role in vascular and cardiovascular health,” said the authors. Studies have shown that circulating calcium levels contribute directly to the development of coronary artery calcification and aortic calcification, two phenomena closely linked to the recurrence of cardiovascular disease.The protective role of vitamin DThe study also revealed that taking calcium supplements without vitamin D is associated with a higher risk of cardiovascular recurrence (HR, 1.21 [95% CI, 1.17–1.25]) than taking calcium supplements with vitamin D (HR, 0.97 [95% CI, 0.93–1.01]). In effect, this means that for patients with a history of CVD, the risk of recurrence is higher with calcium supplementation alone, but not with combined calcium and vitamin D supplementation. “A plausible mechanism would be that vitamin D administered in combination protects vascular walls from atherosclerosis, thereby mitigating the adverse effects of calcium,” the researchers suggested.Higher risks were observed in men (HR, 1.15 [95% CI, 1.09–1.20]) than in women (HR, 1.07 [95% CI, 1.03–1.11]). These sex differences could, among other things, be explained by the fact that men are more susceptible to vascular calcification than women, according to the authors.Important clinical implicationsAccording to the researchers, caution is advised when prescribing or using calcium supplements in patients with CVD. They indicated that the benefits of routine supplementation for bone health remained modest.However, calcium supplements are often necessary in older adults who have both cardiovascular disease (CVD) and osteoporosis. The study authors hence suggested prioritizing calcium supplementation combined with vitamin D, particularly in patients with insufficient sun exposure.“Given the increased risk of recurrent cardiovascular disease, the prescription or use of calcium supplements in patients with cardiovascular disease should be approached with caution,” the authors concluded. “Our observational study results, which are consistent with meta-analyses, suggest that combined calcium and vitamin D supplementation is less of a concern.”The study authors called for the publication of guidelines regarding calcium supplementation in CVD patients, modeled on those recently established for individuals with chronic kidney disease (CKD).ReferenceZhang X, Tan KCB, Kung AWC, Li GHY, Cheung CL. Association between calcium supplementation and recurrence of cardiovascular events in patients with cardiovascular disease: a population-based cohort study. J Am Heart Assoc. 2026;15(8):e047455. doi:10.1161/JAHA.125.047455.This article was initially published on our sister site ProfessionSanté.ca and has been translated from its original French.

Study urges caution with calcium supplements for patients with heart disease

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