title: Relationship between vitamin D and muscle size and strength in patients on hemodialysis.
abstract: OBJECTIVE
  Vitamin D has various actions in skeletal muscle. The purpose of this study was to compare lower-limb muscle size and strength in hemodialysis (HD) patients being treated with 1,25-dihydroxyvitamin D (calcitriol) or a 1,25-dihydroxyvitamin D analogue (paricalcitol) with lower-limb muscle size and strength in HD patients who were receiving none.
  
  
  METHODS
  This was a retrospective, cross-sectional study.
  
  
  METHODS
  This study was performed in outpatient HD centers.
  
  
  METHODS
  Hemodialysis patients receiving calcitriol or paricalcitol (active vitamin D) for control of secondary hyperparathyroidism (VitD, n = 49) were compared with HD patients who were not (n = 30).
  
  
  METHODS
  The main outcome measures included the cross-sectional areas (CSAs) of the thigh and tibialis anterior muscles by magnetic resonance imaging, and three measures of strength: the three-repetition maximum (3RM) for knee extension (isotonic), the peak torque of knee extensors (isokinetic), and maximal voluntary contraction of the ankle dorsiflexor muscles (isometric).
  
  
  RESULTS
  There were no differences in age, weight, dialysis vintage, or intact parathyroid hormone levels between groups, although serum albumin was higher in the VitD group (P < .05). Patients in the VitD group had a larger thigh-muscle CSA (P < .05) and were stronger across all strength measures (P < .05) after controlling for age and gender (by analysis of covariance). When all analyses were subsequently adjusted for serum albumin concentration, only the difference in 3RM knee-extension strength lost significance. There were no significant differences in any measurements between patients who received calcitriol or paricalcitol.
  
  
  CONCLUSIONS
  Treatment with active vitamin D was associated with greater muscle size and strength in this cohort of HD patients.
authors.affiliation: Department of Physiological Nursing, School of Nursing, University of California at San Francisco, 2 Koret Way, San Francisco, CA 94143, USA. patricia.gordon@nursing.ucsf.edu
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Gordon
authors.forename: Giorgos K
authors.initials: GK
authors.lastname: Sakkas
authors.forename: Julie W
authors.initials: JW
authors.lastname: Doyle
authors.forename: Tiffany
authors.initials: T
authors.lastname: Shubert
authors.forename: Kirsten L
authors.initials: KL
authors.lastname: Johansen
mesh_terms: D002117:Calcitriol / Q000627:therapeutic use; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004872:Ergocalciferols / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000517:prevention & control; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology*; D010281:Parathyroid Hormone / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects; D012189:Retrospective Studies; D012709:Serum Albumin / Q000032:analysis / Q000378:metabolism; D014807:Vitamin D / Q000627:therapeutic use*
chemical_list: D004872:Ergocalciferols; D010281:Parathyroid Hormone; D012709:Serum Albumin; D014807:Vitamin D; C084656:paricalcitol; D002117:Calcitriol