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:

1. Adult male or female > 18 years of age

2. Scheduled to undergo bariatric surgery

Exclusion criteria:

1. Vitamin D deficiency

2. Primary hyperparathyroidism

3. Treatment with lithium or thiazide diuretics which may alter PTH levels

4. Osteomalacia

5. Untreated hyperthyroidism, liver disease, Cushing's syndrome, rheumatoid arthritis,
myeloma or Paget's disease

6. Impaired renal function (serum creatinine >2.0mg/dl) or history of renal
osteodystrophy

7. Use of any anti-obesity medications for over 2 weeks 90 days prior to study

8. Participation in any research study 90 days prior to study

9. Any malabsorption syndromes such as celiac sprue

10. Previous bariatric surgery