Objectives: To study the effects of vitamin D supplementation in healthier populations of men.
Design: : Randomized, controlled trial.
Setting: General clinical research center.
Participants: Sixty-five healthy, community-dwelling men (mean age+/-standard deviation=76+/-4, range 65-87).
Intervention: Cholecalciferol (1,000 IU/d) or placebo supplementation for 6 months; all received 500 mg supplemental calcium.
Measurements: Upper and lower extremity muscle strength and power, physical performance and activity, health perception, calcium and vitamin D intake, and biochemical assessment, including 25-hydroxyvitamin D (25OHD), parathyroid hormone (PTH), and ionized calcium levels.
Results: The levels of 25OHD increased and PTH decreased in the cholecalciferol group, whereas there were no significant changes in the control group (P<.001). Baseline 25OHD levels correlated with baseline single-leg stance time and physical activity score. Baseline PTH levels correlated with baseline 8-foot walk time and physical activity score. No significant difference in strength, power, physical performance, or health perception was found between groups.
Conclusion: The 25OHD or PTH levels correlated with physical activity and physical performance in older, community-dwelling men with normal 25OHD status. Vitamin D supplementation increased 25OHD levels and decreased PTH levels but did not increase muscle strength or improve physical performance or health perception in this group of healthy, older men. Further investigations of the effects of vitamin D supplementation should focus on individuals with low levels of vitamin D.