Bone quality: a determinant for certain risk factors for bone fragility

Area of Science:

• Orthopedics
• Gerontology
• Biomaterials Science

Background:

• Low bone quantity alone is insufficient to explain fragility fractures.
• Bone quality, encompassing architecture, matrix, mineralization, and fatigue damage, is critical for fracture risk assessment.
• Age-related changes significantly degrade bone quality, leading to increased fracture susceptibility.

Purpose of the Study:

• To investigate the influence of bone quality on fracture risk in relation to age, sex, and race.
• To elucidate the specific components of bone quality that contribute to age-related bone fragility.
• To explore racial and sexual disparities in bone fragility and their underlying mechanisms.

Main Methods:

• Analysis of bone architecture, matrix properties, mineralization status, and accumulated fatigue damage.
• Comparative assessment of bone quality parameters across different age groups, sexes, and racial populations.
• Examination of bone turnover rates and their correlation with bone quality and fracture incidence.

Main Results:

• Bone trabecular network connectivity and strength decrease with age.
• Aging leads to osteocyte death, resulting in bone hypermineralization and brittleness.
• Accumulated fatigue damage and declining collagen stability contribute to age-related bone fragility.
• Males exhibit lower fragility rates than females due to larger skeletal size, higher cortical bone density post-60, and greater bone turnover.
• Black populations generally have lower fragility fracture rates than white populations, with variations in bone mineral density and turnover rates.
• South African Black individuals show thicker, better-connected trabeculae with less age-related degradation compared to whites.
• Disparities in American and African Black populations suggest a genetic predisposition for higher bone mineral density, with environmental factors (e.g., calcium intake) and lifestyle (e.g., weight-bearing activity) influencing its realization and subsequent bone quality.

Conclusions:

• Bone quality is a critical determinant of fracture risk, independent of bone quantity.
• Age-related deterioration in bone architecture, matrix integrity, and increased fatigue damage significantly elevate fracture risk.
• Racial and sexual differences in bone fragility are influenced by a complex interplay of genetics, skeletal size, bone density, bone turnover, and lifestyle factors.