Objective:

To explore the complex relationship between obesity and bone health, highlighting the paradox of higher bone mineral density (BMD) in obesity not correlating with reduced fracture risk, particularly at peripheral sites.

Approach:

• Positive effects of obesity on bone: Increased body mass enhances mechanical loading, stimulating adaptive changes in bone, and adipose tissue exerts endocrine effects that may temporarily support bone formation.
• Negative effects of obesity on bone: Chronic low-grade inflammation, oxidative stress, and marrow adiposity impair bone quality and compromise microarchitecture, leading to increased fracture risk.

Key Findings:

• Obesity is associated with higher BMD but increased fracture risk at peripheral sites such as the ankle, humerus, and tibia.
• Conventional DXA may overestimate skeletal strength in individuals with obesity due to soft-tissue interference.
• Emerging tools like trabecular bone score and HR-pQCT provide better insights into bone quality, including microarchitecture and cortical porosity.
• Chronic inflammation and oxidative stress negatively impact bone health in obesity.

Interpretation:

The relationship between obesity and bone health is multifaceted, necessitating a comprehensive approach to fracture risk assessment that goes beyond BMD.

Limitations:

• DXA's limitations in assessing true bone strength in the presence of excess soft tissue.
• Potential underestimation of fracture risk due to reliance on BMD alone.

Conclusion:

A comprehensive, individualized approach is essential for assessing and managing fracture risk in individuals with obesity.