Association of 1,25-dihydroxyvitamin D levels with physical performance and thigh muscle cross-sectional area in chronic kidney disease stage 3 and 4

• Published in: Journal of renal nutrition Vol. 22; no. 4; p. 423
• Main Authors: Gordon, Patricia L, Doyle, Julie W, Johansen, Kirsten L
• Format: Journal Article
• Language: English
• Published: United States 01.07.2012
• Subjects: Adult; Aged; Aged, 80 and over; Anatomy, Cross-Sectional; Calcium - blood; Double-Blind Method; Female; Humans; Kidney Failure, Chronic - blood; Kidney Failure, Chronic - complications; Kidney Failure, Chronic - physiopathology; Magnetic Resonance Imaging; Male; Middle Aged; Motor Activity; Multivariate Analysis; Muscle, Skeletal - anatomy & histology; Parathyroid Hormone - blood; Regression Analysis; Serum Albumin - analysis; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - complications; Vitamin D Deficiency - physiopathology
• ISSN: 1532-8503
• DOI: 10.1053/j.jrn.2011.10.006

Declines in 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels and physical functioning follow the course of chronic kidney disease (CKD). Although the molecular actions of vitamin D in skeletal muscle are well known, and muscle weakness and atrophy are observed in vitamin D-deficient states, there is little information regarding vitamin D and muscle function and size in CKD. To examine associations of vitamin D with physical performance (PF) and muscle size. Cross-sectional. CKD clinic. Twenty-six patients (61 ± 13 years, 92% men) with CKD stage 3 or 4. Gait speed, 6-minute walk, sit-to-stand time, 1-legged balance, and thigh muscle cross-sectional area (MCSA), measured by magnetic resonance imaging (MRI). Overall, 73% were 25-hydroxyvitamin D (25(OH)D) deficient (n = 10) or insufficient (n = 9) (Kidney Disease Outcomes Quality Initiative guidelines). 25(OH)D level was associated with normal gait speed only (r = 0.41, P = .04). Normal and fast gait speed, the distance walked in 6 minutes, and sit-to-stand time were best explained by 1,25(OH)₂D and body mass index (P < .05 for all) and 1-legged stand by 1,25(OH)₂D (r = 0.40, P < .05) only. There were no associations of age, estimated glomerular filtration rate (eGFR), intact parathyroid hormone (iPTH), or albumin with any PF measures. MCSA was associated with eGFR (r = 0.54, P < .01) only. Variance in MCSA was best explained by a model containing 1,25(OH)₂D, plasma Ca²⁺, and daily physical activity (by accelerometry) (P < .05 for all). Once these variables were in the model, there was no contribution of eGFR. These results suggest that 1,25(OH)₂D is a determinant of PF and muscle size in patients with stage 3 and 4 CKD.