--Disease Characteristics-- Histologically diagnosed mild asymptomatic primary hyperparathyroidism Persistent albumin adjusted serum calcium between 10.1-11.5 mg/dL for at least 3 months Intact parathyroid hormone greater than 20 pg/mL No other cause for hypercalcemia No family history of primary hyperparathyroidism, primary endocrine neoplasia, or hypocalciuric hypercalcemia Bone mineral density of the forearm no greater than 2.0 SD units below the expected value for sex, age, and race No phalangeal subperiosteal resorption on hand x-rays --Prior/Concurrent Therapy-- Radiotherapy: No history of childhood irradiation to head and neck Surgery: No thyroid disease requiring surgical intervention Other: No prior glucocorticoid or anticonvulsant drug therapy Concurrent thiazide diuretic therapy for hypertension must be changed to nonthiazides --Patient Characteristics-- Menopausal status: At least 5 years postmenopausal Renal: At least 2 years since prior nephrolithiasis Creatinine no greater than 1.5 mg/dL Creatinine clearance at least 70% (age adjusted) Cardiovascular: No unexpected finding on echocardiogram that will interfere with surgical intervention Other: Living within 150 mile radius of downtown Detroit No concurrent participation in other clinical trials No concurrent polyuria, polydipsia, anorexia, nausea, or vomiting At least 12 months since prior pancreatitis No concurrent symptomatic peptic ulcer disease No objective muscle weakness No history of nontraumatic vertebral or hip fractures No vertebral compression fractures No urolithiasis on x-ray of abdomen