Researchers from the University of Auckland said the findings 'suggest that a reassessment of the role of calcium supplements in the prevention and treatment of osteoporosis is warranted'.
The research team performed meta-analysis of 11 studies of calcium supplements.
Although there was no additional risk of stroke or mortality, researchers said that treatment of 1,000 people with calcium for five years would cause an additional 14 MIs.
There would also be an additional 10 strokes and 13 deaths, but calcium treatment would prevent 26 fractures, they added.
Findings were consistent across trials and were independent of age, sex, and type of supplement.
The authors concluded: 'Although the magnitude of the increase in risk is modest, the widespread use of calcium supplements means that even a small increase in incidence of cardiovascular disease could translate into a large burden of disease in the population.'
In an accompanying editorial, Professor John Cleland and colleagues from the University of Hull said calcium supplements seem to be unnecessary in adults with an adequate diet.
'Given the uncertain benefits of calcium supplements, any level of risk is unwarranted,' they wrote.