Hypercalceria If hypercalciuria develops (urinary calcium /creatinine ratio >0.25 on spot urine specimens), the subject will have a 24 hour urine collection performed for confirmation. For confirmed hypercalciuria (>4mg/kg/24 hr), the dose of calcium will be reduced by 250mg and a spot urine repeated one week later. If the abnormality does not resolve, weekly stepwise reductions in calcium will be followed until hypercalceria resolves or supplemental calcium is discontinued. If necessary, vitamin D3 or placebo will be withheld until urine calcium returns to normal.