Analysis of 12 years of health records for 388000 Americans in the NIH-AARP Diet and Health Study found that calcium supplements are associated with an excess risk of CVD death in men but not in women.
Total calcium intake had a U-shaped association with total CVD mortality in men, with increased total CVD mortality observed at calcium intakes of 1500mg/d and higher.
Commentary Are Calcium Supplements Harmful to Cardiovascular Disease? concludes, The paradigm ‘the more the better’ is invalid for calcium supplementation.