Bone Loss After Laparoscopic Roux-en-Y Gastric Bypass
Condition: Bone Loss; Bone Density; Gastric Bypass; Bariatric Surgery
MeSH terms: Bone Diseases, Metabolic
Study type: Observational

Summary: 
      The objective of this study is to assess changes bone mineral density and bone metabolism
      after laparoscopic Roux-en-Y gastric bypass surgery. The investigators hypothesize that
      weight loss after laparoscopic Roux-en-Y gastric bypass surgery will be associated with
      increased bone turnover, changes in bone metabolism, and loss of bone mass.
    

Detailed description: 
      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.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Study population will consist of patients undergoing laparoscopic gastric bypass at a
        community-based teaching institution
      
Biospecimen description: 
      whole blood
    
Keywords: Laparoscopic Gastric Bypass; Morbid Obesity; Bone Mineral Density