title: Vitamin D status predicts physical performance and its decline in older persons.
abstract: BACKGROUND
  Vitamin D deficiency is common among older people and can cause mineralization defects, bone loss, and muscle weakness.
  
  
  OBJECTIVE
  The aim of this study was to investigate the association of serum 25-hydroxyvitamin D (25-OHD) concentration with current physical performance and its decline over 3 yr among elderly.
  
  
  METHODS
  The study consisted of a cross-sectional and longitudinal design (3-yr follow-up) within the Longitudinal Aging Study Amsterdam.
  
  
  METHODS
  An age- and sex-stratified random sample of the Dutch older population was used.
  
  
  METHODS
  Subjects included 1234 men and women (aged 65 yr and older) for cross-sectional analysis and 979 (79%) persons for longitudinal analysis.
  
  
  METHODS
  Physical performance (sum score of the walking test, chair stands, and tandem stand) and decline in physical performance were measured.
  
  
  RESULTS
  Serum 25-OHD was associated with physical performance after adjustment for age, gender, chronic diseases, degree of urbanization, body mass index, and alcohol consumption. Compared with individuals with serum 25-OHD levels above 30 ng/ml, physical performance was poorer in participants with serum 25-OHD less than 10 ng/ml [regression coefficient (B) = -1.69; 95% confidence interval (CI) = -2.28; -1.10], and with serum 25-OHD of 10-20 ng/ml (B = -0.46; 95% CI = -0.90; -0.03). After adjustment for confounding variables, participants with 25-OHD less than 10 ng/ml and 25-OHD between 10 and 20 ng/ml had significantly higher odds ratios (OR) for 3-yr decline in physical performance (OR = 2.21; 95% CI = 1.00-4.87; and OR = 2.01; 95% CI = 1.06-3.81), compared with participants with 25-OHD of at least 30 ng/ml. The results were consistent for each individual performance test.
  
  
  CONCLUSIONS
  Serum 25-OHD concentrations below 20 ng/ml are associated with poorer physical performance and a greater decline in physical performance in older men and women. Because almost 50% of the population had serum 25-OHD below 20 ng/ml, public health strategies should be aimed at this group.
authors.affiliation: Department of Endocrinology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Ilse S
authors.initials: IS
authors.lastname: Wicherts
authors.forename: Natasja M
authors.initials: NM
authors.lastname: van Schoor
authors.forename: A Joan P
authors.initials: AJ
authors.lastname: Boeke
authors.forename: Marjolein
authors.initials: M
authors.lastname: Visser
authors.forename: Dorly J H
authors.initials: DJ
authors.lastname: Deeg
authors.forename: Jan
authors.initials: J
authors.lastname: Smit
authors.forename: Dirk L
authors.initials: DL
authors.lastname: Knol
authors.forename: Paul
authors.initials: P
authors.lastname: Lips
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011237:Predictive Value of Tests; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D