Novel Insight into the Relationship Between Muscle-Fat and Bone in Type 2 Diabetes Ranging from Normal Weight to Obesity

Abstract

Objective

Decreased bone mineral density (BMD) is a common complication in individuals with type 2 diabetes mellitus (T2DM). Body weight, mainly consisting of muscle and fat, is the main determinant of BMD and fracture risks but does not accurately describe nutritional status. Most studies suggest that skeletal muscle mass (SMM) promotes BMD, while body fat mass (BFM) decreases BMD. However, the combined effect of SMM and BFM on BMD is elusive. Thus, the study aims to explore the combined effect of fat and muscle by the ratio index SMM/BFM on BMD in T2DM.

Methods

BFM and SMM were measured by the bioelectrical impedance analysis (BIA) method among 593 T2DM individuals ranging from normal weight and obesity. BMD was analyzed by DXA. Novel non-linear generalized additive models (GAMs) were used as the statistical analysis method.

Results

The results demonstrated that BMD T score/Z score of both femur and lumbar vertebrae were significantly higher and waist–hip ratio (WHR) was significantly lower in the high SMM/BFM group of both normal weight and overweight groups in T2DM individuals. Hence, SMM/BFM might be a good factor indicating BMD in different weight ranges. Additionally, the relationship between muscle fat and BMD was not linear. Notably, this correlation was not influenced by hyperglycemia in T2DM since different analytic models adjusted with the age, gender, BMI and HbA1c were adopted in this study. Furthermore, the impact of trunk fat (central, visceral fat most) and non-trunk fat (peripheral, the sum of subcutaneous limb fat most) on BMD was inconsistent. BMD presented unlimited reduction with trunk BFM increasing, while sustaining minimal diminishment with non-trunk BFM accumulation.

Conclusion

Our study provided a novel viewpoint relationship between muscle-fat and bone, and SMM/BFM might be a potential biomarker for bone health and clinical treatments of diabetes and related metabolic syndromes.

Keywords:

• bone mineral density
• skeletal muscle mass
• body fat mass
• type 2 diabetes
• non-linear correlation

Ethics Approval and Informed Consent

This study protocol was approved by the Institutional Review Board of the Yancheng No.6 Hospital (2018-SR-001), and all participants provided written informed consent. All procedures involved in this study were in accordance with the ethical standards of the Helsinki declaration.

Acknowledgments

The authors acknowledge all the physicians and nurses taking part in the enrolment of participants in the Yancheng city No.6 People’s Hospital, Yancheng, Jiangsu province, China.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This work was financially supported by Yancheng Science and Technology Foundation (YK2020115).