calcuim supplementaion and CVD


OBJECTIVE: To investigate whether calcium supplements increase the risk of cardiovascular events. DESIGN: Patient level and trial level meta-analyses.
DATA SOURCES: Medline, Embase, and Cochrane Central Register of Controlled Trials (1966-March 2010), reference lists of meta-analyses of calcium supplements, and two clinical trial registries. Initial searches were carried out in November 2007, with electronic database searches repeated in March 2010.
STUDY SELECTION: Eligible studies were randomised, placebo controlled trials of calcium supplements (>or=500 mg/day), with 100 or more participants of mean age more than 40 years and study duration more than one year. The lead authors of eligible trials supplied data. Cardiovascular outcomes were obtained from self reports, hospital admissions, and death certificates.
RESULTS: 15 trials were eligible for inclusion, five with patient level data (8151 participants, median follow-up 3.6 years, interquartile range 2.7-4.3 years) and 11 with trial level data (11 921 participants, mean duration 4.0 years). In the five studies contributing patient level data, 143 people allocated to calcium had a myocardial infarction compared with 111 allocated to placebo (hazard ratio 1.31, 95% confidence interval 1.02 to 1.67, P=0.035). Non-significant increases occurred in the incidence of stroke (1.20, 0.96 to 1.50, P=0.11), the composite end point of myocardial infarction, stroke, or sudden death (1.18, 1.00 to 1.39, P=0.057), and death (1.09, 0.96 to 1.23, P=0.18). The meta-analysis of trial level data showed similar results: 296 people had a myocardial infarction (166 allocated to calcium, 130 to placebo), with an increased incidence of myocardial infarction in those allocated to calcium (pooled relative risk 1.27, 95% confidence interval 1.01 to 1.59, P=0.038).
CONCLUSIONS: Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.

Calcium Supplements Reportedly Raise Risk for Myocardial Infarction



Patients on calcium supplements show a modest increase in risk for myocardial infarction, according to a BMJ meta-analysis.

Investigators gathered data on some 12,000 participants in randomized controlled trials using calcium supplements without vitamin D. Subjects on calcium showed a roughly 30% increase in risk for MI and nonsignificant increases for stroke, death, and the composite outcome of MI, stroke, or sudden death.

The authors propose that one mechanism for the effect could be the danger of increased vessel calcification. They estimate that although treating 1000 people for 5 years would prevent 26 fractures, it would also lead to 14 MIs, 10 strokes, and 13 deaths.

An editorial concludes: “Patients with osteoporosis should generally not be treated with calcium supplements, either alone or combined with vitamin D, unless they are also receiving an effective treatment for osteoporosis.”

source:BMJ