Bone structural changes after gastric bypass surgery evaluated by HR-pQCT: a two-year longitudinal study.

Area of Science:

• Endocrinology
• Metabolic Bone Disease
• Bariatric Surgery

Background:

• Roux-en-Y gastric bypass (RYGB) is effective for weight loss but may cause metabolic bone disease.
• Assessing the long-term effects of RYGB on bone health is crucial.

Purpose of the Study:

• To evaluate the impact of RYGB on bone mineral density, volumetric bone mineral density (vBMD), and bone microarchitecture.
• To monitor changes in bone turnover markers (BTMs) and relevant hormones post-RYGB.

Main Methods:

• Dual-energy X-ray absorptiometry (DXA) for bone mineral density at hip and spine.
• High-resolution peripheral quantitative CT (HR-pQCT) for vBMD and microarchitecture at distal radius and tibia.
• Measurement of BTMs, calciotropic hormones, gut hormones, and adipokines at baseline, 12, and 24 months in 25 morbidly obese subjects.

Main Results:

• Significant weight loss (24.1%) at 12 months, followed by weight stabilization.
• Progressive deterioration in cortical and trabecular vBMD and microarchitecture over 24 months.
• Estimated bone strength decreased by 5% (radius) and 7% (tibia) by 24 months; declines were substantial in the second year.

Conclusions:

• Bone loss and deterioration in bone strength continue significantly in the second year after RYGB, despite weight stabilization.
• Metabolic parameters showed initial changes but stabilized after 12 months.
• The findings highlight a potential increased risk of osteoporosis and fragility fractures following RYGB.