Adequate calcium intake is essential for bone health and proper function of other organ systems. But a new study adds to emerging evidence that suggests excessive calcium intake may increase the risk of death from cardiovascular disease.
More than half of US women who are middle aged or older take calcium supplements, in part because of concerns that their dietary intake may fall short. But recent studies have raised concerns about the potential cardiovascular disease risks associated with use of calcium supplements (Bolland MJ et al. BMJ. 2010;341:c3691), and the new study adds to such concerns (Michaëlsson K et al. BMJ. 2013;346:f228). In this prospective longitudinal cohort study of 61 433 women who were followed up for 19 years, the researchers used questionnaires to assess the women's diet and supplement use. They found that women who consumed more than 1400 mg of calcium daily had a higher rate of death from all causes (hazard ratio [HR], 1.40; 95% CI, 1.17-1.67) than women who consumed between 600 mg and 1000 mg daily. Women who consumed more than 1400 mg of calcium daily also had a higher risk of death from cardiovascular disease (HR, 1.49; 95% CI, 1.09-2.02) and ischemic heart disease (HR, 2.14; 95% CI, 1.48-3.09) but not stroke.