Bone quality changes associated with aging and disease: a review

Area of Science:

• Biomedical Engineering
• Orthopedics
• Materials Science

Background:

• Bone quality is crucial for fracture resistance, extending beyond bone mineral density.
• Factors like architecture, porosity, and composition significantly influence bone's mechanical integrity.
• These properties vary with age, health status, and species, necessitating a comprehensive understanding.

Purpose of the Study:

• To review the multifaceted aspects of bone quality beyond density.
• To explore how architectural, compositional, and structural changes affect bone's mechanical performance.
• To correlate age-dependent changes and disease-related alterations in bone quality with fracture risk.

Main Methods:

• Literature review focusing on bone architecture, porosity, and composition (collagen, mineral).
• Analysis of correlations between specific bone quality parameters (e.g., collagen cross-linking, crystallinity) and mechanical performance.
• Comparison of age-related changes in humans and rodents, including models of diseases like osteoporosis.

Main Results:

• Bone quality is determined by a combination of factors including collagen structure, mineral composition, and crystal size.
• Crystallinity, collagen cross-linking, and carbonate content show distinct correlations with mechanical performance compared to mineral content alone.
• Aging and diseases such as osteoporosis, osteomalacia, osteogenesis imperfecta (OI), and osteopetrosis distinctly alter bone quality, increasing fracture risk.

Conclusions:

• Bone quality is a complex trait influenced by multiple factors beyond just density.
• Understanding these factors is critical for assessing fracture risk in aging populations and in various bone diseases.
• Rodent models provide valuable insights into human bone diseases and age-related bone quality changes.