Bone Loss After Laparoscopic Roux-en-Y Gastric Bypass

Obesity is an increasing problem within the United States. Fifteen million people in the
United States are considered morbidly obese, with a body mass index (BMI) greater than 40
kg/m2. A wealth of literature has shown laparoscopic Roux-en Y gastric bypass surgery to be
an effective procedure to reduce excess body weight. But a paucity of research examines the
effects of laparoscopic Roux-en Y surgery on the skeleton.

Bone remodeling is a complex process involving bone resorption and formation-a process
dependent upon local and systemic influences. Obesity is one of these influences that is
poorly understood. Obesity is associated with a reduced risk of osteoporosis. Obesity may be
protective due to increased weight bearing, increased production of estrogen by adipose
tissue, or increased bone formation due to higher levels of insulin.

It is known that weight loss in healthy individuals is associated with bone loss. Several
small studies have reported bone loss in patients undergoing vertical band gastroplasty or
jejunoileal bypass weight loss surgeries. Other reported metabolic disease disarrangements
following weight loss surgery are decreased serum calcium, decreased serum 25-hydroxy
vitamin D, and hyperparathyroidism.

In the bariatric literature, weight loss has been associated with an increased risk of bone
mineral loss and fracture. Osteoporosis has been described in patients who lost weight after
jejunoileal bypass surgery. Premenopausal women appeared to be spared from bone mineral
loss, thus indicating a protective effect from the premenopausal state. Bone mineral loss is
seen both in premenopausal women and in men after weight loss surgery.

Roux-en Y gastric bypass has been shown to be more effective at weight loss than has the
adjustable silicone gastric band. It has also been linked with increased loss of bone
mineral density. Another study found an increase in bone turnover as well as a decrease in
total bone mass and trochanteric bone density in laparoscopic Roux-en Y gastric bypass
patients.

Previous research at our institution has shown a statistically significant increase in the
prevalence of hyperparathyroidism in post-gastric bypass patients. However, our previous
research did not examine the impact that these hormonal changes impart upon bone density. We
have found a statistically significant incidence of vitamin D deficiency in our patients
following this surgery. We intend to expand upon our own research as well as that of others
by exploring the associations between the development of hyperparathyroidism, bone metabolic
derangements, weight loss, and bone density.

Inclusion Criteria:

- Morbidly obese female patients undergoing elective laparoscopic Roux-en-Y gastric
bypass at a single institution

Exclusion Criteria:

- Male patients

- Patients unable to fulfill the study protocol requirements