title: Body size and serum 25 hydroxy vitamin D response to oral supplements in healthy older adults.
abstract: BACKGROUND
  Vitamin D insufficiency is prevalent in the northeast United States. Since vitamin D insufficiency is readily amenable to supplementation, it is important to understand what factors are associated with serum 25 hydroxy vitamin D (25(OH)D) response to vitamin D supplementation.
  
  
  OBJECTIVE
  In this study we examined the association of serum 25(OH)D response to vitamin D supplementation with body size in a population of elderly subjects.
  
  
  METHODS
  257 healthy, ambulatory men and women 65 years of age or older were randomly assigned to treatment with either 700 IU/day (17.5 microg/d) of supplemental vitamin D(3) and 500 mg/day (12.5 mmol/d) of supplemental calcium, or to placebo.
  
  
  RESULTS
  In multivariate regression analyses, after adjusting for baseline 25(OH)D, season, and sex, we found change in 25(OH)D to be inversely associated with baseline BMI (p = 0.01) in subjects treated with supplements for one year. Change in 25(OH)D was also negatively associated with other baseline anthropometric measurements in these subjects.
  
  
  CONCLUSIONS
  Our study implies that body size should be taken into account when estimating the amount of vitamin D intake needed to raise 25(OH)D to the desired level.
authors.affiliation: Bone Metabolism Laboratory, Jean Mayer USDA, HNRC on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
authors.forename: Miriam
authors.initials: M
authors.lastname: Blum
authors.forename: Gerard E
authors.initials: GE
authors.lastname: Dallal
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition / Q000187:drug effects / Q000502:physiology; D015992:Body Mass Index; D002762:Cholecalciferol / Q000008:administration & dosage*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D012044:Regression Analysis; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D