The investigators plan to conduct a clinic-based interventional study of 30 patients followed at outpatient urology clinics associated with New York Presbyterian Hospital (NYPH). The intervention is supplementation with oral ergocalciferol 50,000 IU per week for 8 weeks, and each participant will serve as his/her own control. The formulation, dose, and duration of vitamin D therapy is reflective of that which is given in routine clinical practice to patients with vitamin D deficiency. The outcome is the change in urinary calcium excretion.
