Researchers undertook a randomised, double blind, placebo controlled trial to assess whether calcium supplementation was associated with adverse cardiovascular events.1 Healthy postmenopausal women were recruited and randomly assigned to receive five tablets a day of either 200 mg of elemental calcium or identical placebo. The occurrence of adverse cardiovascular events over a five year period was recorded. Calcium supplementation in healthy postmenopausal women was associated with increased rates of adverse cardiovascular events.

Which of the following statements, if any, are true?

• a) The placebo was an inert treatment with no …