Intestinal Calcium Absorption Decreases After Laparoscopic Sleeve Gastrectomy Despite Optimization of Vitamin D...

Area of Science:

• Bariatric surgery
• Metabolic and endocrine disorders
• Bone metabolism

Background:

• Laparoscopic sleeve gastrectomy (LSG) is the most common bariatric procedure for obesity.
• Roux-en-Y gastric bypass impairs calcium absorption and bone health.
• LSG's impact on calcium homeostasis and bone health is not well understood.

Purpose of the Study:

• To evaluate the effect of LSG on fractional calcium absorption (FCA).
• To assess changes in calcium homeostasis and bone health markers post-LSG.
• To determine if LSG impacts bone mineral density (BMD).

Main Methods:

• Prospective observational cohort study of 35 adults with severe obesity undergoing LSG.
• Dual stable isotope method to measure FCA preoperatively and 6 months postoperatively.
• Assessed calciotropic hormones, bone turnover markers, and BMD using DXA and QCT.

Main Results:

• Mean FCA decreased significantly from 31.4% to 16.1% post-LSG (P < 0.01).
• Bone turnover markers increased, and areal BMD decreased at the proximal femur.
• Lower postoperative FCA correlated with greater BMD loss at the total hip (ρ = 0.45, P < 0.01).

Conclusions:

• LSG leads to decreased FCA and negative skeletal effects, including increased bone turnover and reduced BMD.
• These skeletal changes occur despite adequate 25-hydroxyvitamin D levels and recommended calcium intake.
• Reduced FCA following LSG may contribute to adverse bone health outcomes.