Occupational sitting and low hip mineral density

Area of Science:

• Bone Biology and Remodeling
• Occupational Health
• Osteoporosis Research

Background:

• Habitual physical activity plays a role in maintaining bone health.
• Understanding the impact of occupational physical activity on bone mineral density (BMD) is crucial for public health.

Purpose of the Study:

• To evaluate the contribution of habitual physical activity to bone remodeling.
• To compare bone mineral density (BMD) between individuals with predominantly sitting versus standing occupations.

Main Methods:

• Dual-energy X-ray absorptiometry (DXA) was used to measure BMD at the lumbar spine (L2-4) and hip.
• Bone mineral density (BMD) was assessed in 55 clerks (sitting occupation) and 44 nurses (standing occupation).
• Serum osteocalcin levels and duration of standing at work were analyzed in relation to hip BMD.

Main Results:

• Similar lumbar spine (L2-4) BMD was observed in both clerks and nurses.
• Nurses exhibited significantly higher femur BMD compared to clerks (0.6-0.8 SD at various hip sites).
• Age-adjusted hip BMD correlated with serum osteocalcin and was related to the duration of standing at work.

Conclusions:

• Prolonged working in a sitting position may lead to lower hip bone mineral density (BMD).
• This reduction in hip BMD is associated with an increased risk of osteoporotic hip fracture.
• Occupational physical activity, particularly standing, appears to be a protective factor for hip bone health.