The relationship of Physical performance and Osteoporosis prevention with vitamin D in older African Americans (PODA)

Rationale: Vitamin D deficiency is associated with bone loss, poor muscle strength, falls and fracture. This information in older African Americans (AAs) is sparse. Objective: The study of the relationship of Physical performance, Osteoporosis prevention with vitamin D in older African Americans (PODA) is a randomized, double-blind, placebo-controlled 3-year trial examining the effect of vitamin D on bone loss and physical performance in older AA women. Methods: 260 healthy AA women aged > 60 years were assigned to receive placebo or vitamin D3. Initial vitamin D3 dose was determined by the baseline serum 25OHD level, and adjusted further to maintain serum 25OHD between 30 and 69 ng/ml. Subjects with baseline 25OHD levels <= 8 ng/ml or >= 26 ng/ml were excluded. Objective measures of neuromuscular strength [Short Physical Performance Battery (SPPB), grip strength and 6-minute walking distance (6MWD)] and bone mineral density (BMD) were obtained. Results: SPPB gait speed, grip strength and 6MWD showed a significant positive correlation with free 25OHD. 1 pg/ml increase in free 25OHD predicted a 32% increase in the odds of having higher gait speed and a 1.42 1b. increase in grip strength. No significant differences in BMI, BMD, muscle mass, grip strength, serum total 25OHD and free 25OHD were observed between groups. None of the measures of physical performance showed an association with baseline serum 25OHD. Conclusions: This is the first study to show an association between free 25OHD and physical performance. These findings indicate a positive relationship of free 25OHD with gait speed and grip strength in older AA women. Further studies are needed to understand the role of free 25OHD.