Bone Abstracts

Introduction: Vitamin D deficiency is common among elderly subjects and is associated with reduced muscle strength. Although vitamin D deficiency is common among Saudi subjects, knowledge about its role in relation to muscle strength and physical performance is lacking. The objectives of the present study are to determine vitamin D status in a sample of randomly selected healthy postmenopausal Saudi women and to investigate the association between their serum 25(OH)D levels and measures of physical performance.

Subjects and method: A total of 223 healthy postmenopausal women (age: ≥50 years) were randomly recruited from the city of Jeddah, medically examined and provided fasting blood samples for assessment of 25(OH)D and parathyroid hormone (PTH). Physical functions were assessed by the following tests: get up and go (GUG); eight-feet walk (8FW); five-times sit to stand (5-STS). Women were stratified into tertiles of serum 25(OH)D during statistical analysis.

Results: A total of 39, 77, and 95% of women had serum 25(OH)D levels <25, <50, and <75 nmol/l; respectively. A weak correlation approaching significance was found between 25(OH)D and GUG (r=−0.132; P<0.051). However, after adjusting for age and BMI the correlation disappeared. There was no significant difference in any of the measures of physical performance between women in the upper (25(OH)D levels ≥38.8 nmol/l) and those in the lower (25(OH)D levels <22.9 nmol/l) tertiles of 25(OH)D levels. Serum PTH levels was not significantly associated with any of the physical performance measures.

Conclusion: The present study suggests that low vitamin D status (25(OH)D <50 nmol/l) is not associated with poor physical performance and may be a reflection of muscle adaptation to prolonged duration of vitamin D deficiency.