Effects of Laparoscopic Sleeve Gastrectomy on Bone Mineral Density and Bone Metabolism in Chinese Patients with Obesity

Abstract

Objective

Laparoscopic sleeve gastrectomy (LSG) is one of the most effective therapies to treat obesity. Due to a lack of longitudinal research, we explored the changes in BMD and bone metabolism in Chinese patients with obesity before and after LSG.

Materials and Methods

A total of 49 obese Chinese patients with obesity were recruited from the Second Xiangya Hospital of Central South University. All patients underwent LSG, and the metabolic indicators were evaluated, including the serum osteocalcin (OC), total-terminal propeptide of type I procollagen (TPINP) and carboxy terminal telopeptide of collagen type I (CTX) levels at baseline and 2, 6 and 12 months postoperatively. Dual energy X-ray absorptiometry (DEXA) was used to measure body composition and BMD before and 12 months after LSG.

Results

The body mass index (BMI) significantly decreased at 12 months postoperatively, and no patients developed osteoporosis. The BMD of femoral neck and total hip significantly decreased from the baseline to 12 months postoperatively, while the BMD of lumbar spine did not change significantly. The OC, TPINP and CTX levels significantly increased at 12 months postoperatively. The excess BMI loss (EBMIL) was positively related while the reduction in visceral adipose tissue (VAT) mass was negatively related to the decreases in BMD of the femoral neck and total hip at 12 months postoperatively. The increase in OC was negatively correlated with the decrease in BMD of the femoral neck, while the increase in TPINP was positively correlated with the decrease in BMD of total hip.

Conclusion

Based on the 12-month follow-up results, the BMD of the femoral neck and total hip was decreased in Chinese patients with obesity after LSG, while bone remodelling was active. This finding suggested that weight loss, a decrease in the VAT mass and an increase in bone remodelling may be correlated with a reduction in BMD.

Keywords:

• laparoscopic sleeve gastrectomy
• obesity
• bone mineral density
• bone metabolism markers

Abbreviations

BMD, bone mineral density; BMI, body mass index; CSU, Central South University; CTX, carboxy terminal telopeptide of collagen type I; DEXA, dual energy X-ray absorptiometry; EBMIL, excess BMI loss; FCP, fasting C-peptide; FPG, fasting plasma glucose; HbA_1c, haemoglobin A_1c; iPTH, intact parathyroid hormone; LSG, laparoscopic sleeve gastrectomy; OC, osteocalcin; QCT, quantitative computed tomography; RYGB, Roux-en-Y gastric bypass; TPINP, total-terminal propeptide of type I procollagen; VAT, visceral adipose tissue.

Acknowledgment

We thank Zhongjian Xie (Department of Metabolism and Endocrinology, Hunan Provincial Key Laboratory of Metabolic Bone Diseases and National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China) for critically reading the manuscript.

Disclosure

The authors declare that they have no conflicts of interest.

Additional information

Funding

This study was supported by the National Key R&D Program of China (2016YFC1305000, 2016YFC1305001), the National Natural Science Foundation of China (91749118, 81770775, 81670481), the Science and Technology Major Project of Hunan Province (2017SK1020) and the Planned Science and Technology Project of Hunan Province (2017RS3015).