Calcium supplementation and the risks of atherosclerotic vascular disease in older women: Results of a 5-year RCT and a 4.5-year follow-up

Abstract

Concern has been expressed that calcium supplementation, a key intervention for preventing osteoporotic fracture in older women, may increase the risk of atherosclerotic vascular disease. To evaluate the risk further, an examination of complete verified atherosclerotic vascular hospitalization and mortality data from a 5-year randomized, controlled trial (RCT) of calcium carbonate and 4.5 years of posttrial follow-up was undertaken. This study used data from a published 5-year randomized, double-blinded, placebo-controlled trial [Calcium Intake Fracture Outcome Study (CAIFOS)]. The participants were 1460 women aged 75.1 AE 2.7 years at baseline (1998) recruited from the general population and randomized to receive 1200 mg of calcium carbonate daily or an identical placebo. All hospital admission and deaths during the 5-year study and the 4.5-year follow-up were derived from the Western Australian Data Linkage Service (WADLS). Hazard ratios (HRs) for the combined endpoint of atherosclerotic vascular mortality or first hospitalization were calculated using prespecified intention-to-treat and per-protocol models. The intervention group that received calcium supplementation did not have a higher risk of death or first-time hospitalization from atherosclerotic vascular disease in either the 5-year RCT [multivariate-adjusted HR ¼ 0.938, 95% confidence interval (CI) 0.690-1.275] or during the 9.5 years of observational study (multivariate-adjusted HR ¼ 0.919, 95% CI 0.737-1

Feasibility of a clinical trial to assess the effect of dietary calciumv.supplemental calcium on vascular and bone markers in healthy postmenopausal women

“…The regular monthly follow-ups allowed close monitoring of protocol adherence and further counselling to ensure adherence to the trial protocol. We observed a high compliance of 85 % to Ca supplements, whereas comparable trials reported compliance rates between 59 and 85 % (6,16,(53)(54)(55) . We also observed that the rigorous design of our pilot trial was effective to help achieve the target dietary Ca in each group at monthly follow-ups.…”

“…cardiovascular events (15)(16)(17)(18) . On the other hand, most studies demonstrated that dietary sources of Ca have not been linked with cardiovascular adverse events (13,19,20) or have been shown to be favourable to cardiovascular health (21)(22)(23)(24) .…”

Dietary calcium intake in a cohort of elderly patients already in drug therapy for osteoporosis. Is it possible and how to modify the eating habits before calcium supplementation?

“…On the other hand, the possibility that excessive intake of calcium can lead to an increased risk of myocardial infarction and/or ischemic brain lesions has been repeatedly highlighted in the literature. [5][6][7] The absorption of calcium is more regular when we use calcium via the diet regard to calcium via the supplemen- Dietary calcium intake in elderly patients with osteoporosis tation. 8 Calcium intake via the diet reduces considerably the possibility of a transient rise in serum calcium levels that many authors consider the main cause of the increased risk of vascular calcifications.…”

Potential negative cardiovascular effects of calcium supplements

“…According to Reid and colleagues [3], such trials cannot be envisaged for reasons of practicality and ethical obstacles. But there is one such study, and it showed no negative cardiovascular effects [7].…”