# Bone Health After Metabolic and Bariatric Surgery: Osteometabolism Biomarkers, Bone Mineral Density, and Microarchitecture

## TL;DR

This study examines how Roux-en-Y gastric bypass surgery affects bone health, finding negative impacts on bone metabolism and microarchitecture.

## Contribution

The study reveals specific detrimental effects of Roux-en-Y gastric bypass on bone biomarkers and microarchitecture within 2–5 years post-surgery.

## Key findings

- Patients who underwent Roux-en-Y gastric bypass had higher phosphorus, PTH, CTX-1, and P1NP levels compared to controls.
- HR-pQCT showed significant impairments in trabecular thickness and cortical bone density in post-surgery patients.
- Tibia-specific trabecular microarchitecture was impaired in surgical patients despite similar BMD measurements.

## Abstract

The effects of metabolic and bariatric surgery on bone health still require further investigation. Osteometabolism biomarkers, bone microarchitecture (BM), and mineral density (BMD) of patients who have undergone Roux‐en‐Y gastric bypass (RYGB) within 2–5 years from surgery were compared to non‐surgical age‐, sex‐, and BMI‐matched controls.

This cross‐sectional study included 39 patients following RYGB (BG: aged = 39 ± 5 years, BMI = 42.2 ± 3.8 kg/m2) and 21 controls (CG). Circulating levels of albumin, calcium, phosphorus, magnesium, 25(OH) vitamin D, parathyroid hormone (PTH), carboxy‐terminal telopeptide of type 1 collagen (CTX‐1), and amino‐terminal propeptide of type 1 procollagen (P1NP) were assayed. BMD and BM were assessed by dual‐energy X‐ray absorptiometry (DXA) and three‐dimensional high‐resolution peripheral quantitative computed tomography system (HR‐pQCT).

BG presented with higher circulating phosphorus, PTH, CTX‐1, and P1NP and lower 25(OH) vitamin D compared to CG. DXA parameters did not differ between groups. However, HR‐pQCT revealed significant derangements in BM (trabecular thickness, cortical bone density, and outer trabecular volumetric BMD) in BG. BG showed tibia‐specific trabecular microarchitecture impairment, while sex and BMI showed the expected associations with BM measures.

RYGB was associated with detrimental effects on osteometabolism biomarkers, as well as on density and structural parameters of BM. Early preventive strategies aimed at mitigating these deleterious effects should be systematically evaluated to minimize their long‐term impact.

Trial Registration:
ClinicalTrials.gov (NCT04193397)