title: Effect of vitamin D nutritional status on muscle function and strength in healthy women aged over sixty-five years.
abstract: BACKGROUND
  Vitamin D insufficiency is common in elderly adults, and leads to secondary hyperparathyroidism, bone loss, muscle weakness, and osteoporotic fractures.
  
  
  OBJECTIVE
  To evaluate the relation between vitamin D nutritional status and muscle function and muscle strength in women aged over 65 years.
  
  
  METHODS
  Fifty-four postmenopausal women from Buenos Aires (latitude 34° S), average age (X±DS) 71±4, were included in the study. Determinations of serum calcium, phosphate, 25 hydroxyvitamin D (25OHD), intact parathormone (iPTH) and calciuria / creatininuria ratio in 24-hour urine samples were performed. Muscle function was assessed by means of walking-speed test, standing balance, and sit-to-stand tests. Lower extremity muscle strength was determined using a manual dynamometer.
  
  
  RESULTS
  25OHD levels ≥20 ng/ml were found to be associated with better lower extremity muscle function and strength. Forty- six % of participants had 25OHD levels ≥20 ng/ml. Women with 25OHD levels ≥20 ng/ml scored higher on the muscle function tests (11.2±0.9 vs.10.0±2.1; p<0.003) and had stronger knee extensor (13.4±2.7 vs.11.6±2.5 Kg.; p<0.03) and hip abductor (8.3±2.7 vs. 7.3±3.1 Kg; p<0.04) muscles; strength of their hip flexors tended to be higher but did not reach significantly different values (17.0±3.3 vs. 15.4±2.8 Kg.; 0.1>p>0.05). Negative correlation was observed between iPTH and muscle function (r= -0.436; p<0.02).
  
  
  CONCLUSIONS
  25OHD levels ≥20 ng/ml are needed for a better muscle function and strength. Assessing vitamin D nutritional status in adults aged ≥ 65 years would allow correcting hypovitaminosis D and improve muscle function and strength.
authors.affiliation: Sección Osteopatías Médicas, Hospital de Clínicas, Universidad de Buenos Aires, Buenos Aires, Argentina. Silvinamastaglia@hotmail.com
authors.forename: S R
authors.initials: SR
authors.lastname: Mastaglia
authors.forename: M
authors.initials: M
authors.lastname: Seijo
authors.forename: D
authors.initials: D
authors.lastname: Muzio
authors.forename: J
authors.initials: J
authors.lastname: Somoza
authors.forename: M
authors.initials: M
authors.lastname: Nuñez
authors.forename: B
authors.initials: B
authors.lastname: Oliveri
mesh_terms: D000368:Aged; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D009068:Movement; D053580:Muscle Strength / Q000502:physiology*; D018908:Muscle Weakness / Q000097:blood / Q000517:prevention & control*; D018482:Muscle, Skeletal / Q000502:physiology* / Q000503:physiopathology; D009752:Nutritional Status; D010281:Parathyroid Hormone / Q000097:blood; D010809:Physical Fitness; D017698:Postmenopause; D004856:Postural Balance; D015995:Prevalence; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology*; D016138:Walking
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D