If hypercalcemia (>10.5 mg/dl, albumin-corrected) develops, the dose of calcium will be reduced by 250 mg/day and the levels rechecked one week later. If the abnormality does not resolve, weekly stepwise reductions in oral calcium will be followed until a normal level is achieved or supplemental calcium is discontinued. Vitamin D3 or placebo will be withheld until serum calcium returns to normal.