Subclinically low BMD in young men is associated with compromised bone microarchitecture and lower lean mass

Area of Science:

• Orthopedics
• Endocrinology
• Human Physiology

Background:

• Optimizing bone mass accrual in early life is crucial for mitigating age-related fracture risk.
• Understanding factors contributing to suboptimal bone mass in young adults is essential for preventative strategies.

Purpose of the Study:

• To identify factors associated with lower than expected areal bone mineral density (aBMD) in healthy young adult men.
• To compare bone microarchitecture, body composition, and relevant biomarkers between men with lower and normal aBMD.

Main Methods:

• Dual-energy X-ray absorptiometry (DXA) assessed aBMD and body composition in 39 men.
• High-resolution peripheral quantitative computed tomography (HR-pQCT) evaluated tibial bone quality.
• Enzyme-linked immunosorbent assays measured bone turnover markers, hormones (testosterone, estradiol, PTH), and growth factors (IGF-1, IGFBP-5).

Main Results:

• The 'Lower' aBMD group (Z scores <-1.0) was older, shorter, and had less lean mass compared to controls (Z scores ≥1.0).
• Compromised tibial bone microarchitecture (trabecular number, separation) and strength (stiffness, failure load) were observed in the Lower group.
• The Lower group exhibited higher alkaline phosphatase and lower insulin-like growth factor-1 (IGF-1) concentrations.

Conclusions:

• Young men with relatively lower aBMD exhibit poorer bone microarchitecture and reduced lean mass.
• These findings underscore the importance of lean mass accrual during young adulthood for long-term bone health and fracture prevention.