 - Study schedule with study interventions and frequencies is set out below see table. All 4 groups will adhere to the same schedule. After obtaining consent, subjects will have a Baseline Visit, which will include: 1 a complete physical examination; 2 laboratory evaluation that includes measurement of 25OHD, which is the major circulating form of vitamin D and reflects the bodys vitamin D stores. Additional blood and urine samples will be obtained for measurement of urinary calcium excretion and serum Calcium and parathyroid hormone PTH; and 3 Dietary calcium intake questionnaire. 4 Start of study medication. 