Recently an article from Cleveland Clinic was published regarding hazards of oral calcium taken for a long time.They carried out a long study and  concluded that calcium taken for various conditions for a long time can be deposited in coronary arteries which can lead to heart problems.Many patients require an intake of oral calcium for various conditions for a long time like osteoporosis, postmenopausal women etc. what should be the safety dosage and  duration for oral calcium supplements as dietary supplements are not adequate to meet the demand?