Bone metabolic changes in Antarctic wintering team members

Area of Science:

• Human physiology
• Bone metabolism
• Environmental health

Background:

• Antarctic research stations present unique environmental challenges, including prolonged periods of low sunlight.
• Understanding the impact of such environments on bone health is crucial for long-duration missions.

Purpose of the Study:

• To investigate the effects of a 1-year Antarctic winter stay on bone mass, bone metabolic markers, and calcium regulation hormones.
• To assess seasonal variations in these parameters in a controlled, isolated environment.

Main Methods:

• Measurements of bone mineral density (BMD) using single X-ray absorptiometry (SXA) and quantitative ultrasound (QUS) parameters (Speed of Sound - SOS, Broadband Ultrasound Attenuation - BUA).
• Analysis of bone metabolic markers (bone-specific alkaline phosphatase, osteocalcin, urinary pyridinoline, deoxypyridinoline) and calcium regulation hormones (serum 1,25(OH)2D3, serum 25(OH)D3, serum parathyroid hormone - PTH).
• Longitudinal study of 31 healthy males at Syowa Station, Antarctica.

Main Results:

• No significant seasonal changes in calcaneal BMD by SXA were observed.
• QUS measurements showed a decrease in SOS (0.55%) and an increase in BUA (1.9%).
• Serum 25(OH)D3 levels significantly decreased during winter (p < 0.001), while PTH levels increased (p < 0.01). Bone-specific alkaline phosphatase and osteocalcin increased during summer (p < 0.001).

Conclusions:

• A 1-year stay in Antarctica led to a significant decrease in serum 25(OH)D3 levels, correlated with reduced sunlight exposure.
• Despite hormonal and marker changes, bone mass remained stable, suggesting compensatory mechanisms or resilience.
• The study highlights the impact of environmental factors on vitamin D status and bone metabolism markers in isolated polar environments.