Prospective Study of Hormone Levels After Bariatric Surgery

Subjects will be recruited from the outpatient obesity and surgical clinics at Columbia-Presbyterian Medical Center after they have chosen to undergo a surgical procedure. The groups will not be randomized. Rather, they will decide on their choice of surgery along with their physicians. The patients will be evaluated pre-operatively and followed post-operatively for 5 years.

Initial evaluation will include a complete history and physical examination, measurement of calcium, parathyroid hormone (PTH) and vitamin D, and assessment of skeletal health using markers of bone turnover and bone mineral density.

Inclusion criteria

• Adult male or female > 18 years of age
• Scheduled to undergo bariatric surgery

Exclusion criteria

• Vitamin D deficiency
• Primary hyperparathyroidism
• Treatment with lithium or thiazide diuretics which may alter PTH levels
• Osteomalacia
• Untreated hyperthyroidism, liver disease, Cushing's syndrome, rheumatoid arthritis, myeloma or Paget's disease
• Impaired renal function (serum creatinine >2.0mg/dl) or history of renal osteodystrophy
• Use of any anti-obesity medications for over 2 weeks 90 days prior to study
• Participation in any research study 90 days prior to study
• Any malabsorption syndromes such as celiac sprue
• Previous bariatric surgery