Recently a scientific/medical paper was released saying calcium supplements were shown to increase the risk of heart attacks (myocardial infarctions). Scientific Chick (a Canadian scientist and blogger) read the paper, analyzed it and reached the conclusion:
".....one cannot assume that calcium/vitamin D supplements would lead to the same risks. In fact, another recent study in women reported that calcium and vitamin D administered together had no effect on the risk of heart disease. It’s also important to remember that when weighing risks and benefits, calcium (and vitamin D) does a lot more than just strengthen your bones: it has also been shown to play a role in the prevention of certain cancers. "
Read her entire post here.