Reanalysis of data indicates calcium supplements may increase myocardial infarction, stroke risk
WEDNESDAY, April 20 (HealthDay News) -- Use of personal calcium supplements -- with or without vitamin D -- modestly increases the risk of cardiovascular events, especially myocardial infarction (MI), a finding obscured in the Women's Health Initiative Calcium/Vitamin D Supplementation Study (WHI CaD Study), according to an article published online April 19 in BMJ.
Mark J. Bolland, M.B.Ch.B., from the University of Auckland in New Zealand, and colleagues reanalyzed the effects of personal calcium supplement use on cardiovascular risk in participants of the WHI CaD Study. Data from eight available studies were incorporated into a meta-analysis with data from the WHI CaD Study. The incidence of MI, coronary revascularization, death from coronary heart disease, and stroke, alone or in combination, was measured.
The researchers found that, in the WHI CaD Study, the risk of cardiovascular events increased in women who were not taking calcium supplements at the time of randomization, and were allocated to calcium and vitamin D (hazard ratio range, 1.13 to 1.22), but it remained unaltered in those taking supplements. Meta-analyses of three new studies showed an increased risk of MI, stroke, and a composite of MI or stroke (relative risks, 1.21, 1.20, and 1.16, respectively) with calcium and vitamin D. Of the 28,072 participants included in the pooled data, 1,384 had incident MI or stroke. An increased risk of MI or MI and stroke together (relative risks, 1.24 and 1.15, respectively) was evident in participants who took calcium supplementation with or without vitamin D.
"[These results] strongly suggest that calcium supplements modestly increase the risk of cardiovascular events, particularly myocardial infarction," the authors write.
One author disclosed a financial relationship with the dairy industry. The study medications were supplied by Mission Pharmacal, Shire Pharmaceuticals, and Nycomed.