Objective
Inadequate vitamin D status is related to increased adiposity, risk of falls, and muscle weakness, particularly in the elderly. We hypothesized that serum 25-hydroxyvitamin D (25(OH)D) is related to physical fitness indices (androidal fat, whole body lean mass, balance, strength) in healthy postmenopausal women.
Design
Covariates for fitness indices included: age or years since menopause; weight; 25(OH)D; energy expenditure; calcium intake. Overall and regional (androidal fat mass=waist+hip fat) body composition was assessed (N=242) via dual-energy X-ray absorptiometry.
Results
Regression analyses revealed that 71% of variability (P≤0.0001) in androidal fat mass was accounted for by weight (53.0%, P≤0.0001), white blood cell (WBC) count (2.0%, P≤0.0001), supplemental calcium (1.7%, P=0.0004), years since menopause (1.1%, P=0.0034), 25(OH)D (1.0%, P=0.0051), and vegetable servings (0.6%, P=0.027); 64% of variability (P≤0.0001) in lean mass was accounted for by weight (63.1.%, P≤0.0001), WBC count (1.4%, P=0.0038), and 25(OH)D (1.0%, P=0.013); 12% of variability (P≤0.0001) in balance (right+left leg) was accounted for by age (3.8%, P=0.0019), 25(OH)D (2.0%, P=0.025), and WBC count (1.8%, P=0.032); 14% of variability (P≤0.0001) in hand grip strength (right+left) was accounted for by weight (9.3%, P≤0.0001), 25(OH)D (2.4%, P=0.013), WBC count (2.1%, P=0.019), and age (1.6%, P=0.044); 22% of variability (P≤0.0001) in torso strength was accounted for by site (15.0%, P≤0.0001) and weight (4.6%, P=0.0003).
Conclusion
Serum 25(OH)D was the common contributor to physical fitness indices (androidal fat mass, lean mass, balance, hand grip strength) in healthy postmenopausal women.