title: Change in 25-hydroxyvitamin D and physical performance in older adults.
abstract: BACKGROUND
  Vitamin D deficiency is common among older adults and is associated with poor physical performance; however, studies examining longitudinal changes in 25-hydroxyvitamin D (25[OH]D) and physical performance are lacking. We examined the association between 25(OH)D and physical performance over 12 months in older adults participating in the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P), a multicenter physical activity intervention trial.
  
  
  METHODS
  Plasma 25(OH)D and physical performance, assessed by the short physical performance battery (SPPB) and 400-m walk test, were measured at baseline, 6-month, and 12-month follow-up in community-dwelling adults aged 70-89 years at risk for disability (n = 368). Mixed models were used to examine the association between 25(OH)D and physical performance adjusting for demographics, intervention group, season, body mass index, and physical activity.
  
  
  RESULTS
  One half of the participants were vitamin D deficient (25[OH]D < 20 ng/mL) at baseline. In cross-sectional analyses, vitamin D deficiency was associated with lower SPPB scores and slower 400-m walk speeds (mean difference [SE]: 0.35 [0.16], p = .03 and 0.04 [0.02] m/s, p = .01, respectively). Although baseline 25(OH)D status was not significantly associated with change in physical performance over 12 months, individuals who were vitamin D deficient at baseline but no longer deficient at follow-up had significant improvements in SPPB scores (mean difference [SE]: 0.55 [0.22], p = .01) compared with those whose 25(OH)D status remained the same.
  
  
  CONCLUSIONS
  Increases in 25(OH)D to greater than or equal to 20 ng/mL were associated with clinically significant improvements in physical performance among older adults.
authors.affiliation: Sticht Center on Aging, Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157-1207, USA. dhouston@wfubmc.edu
authors.forename: Denise K
authors.initials: DK
authors.lastname: Houston
authors.forename: Janet A
authors.initials: JA
authors.lastname: Tooze
authors.forename: Dorothy B
authors.initials: DB
authors.lastname: Hausman
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Johnson
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Nicklas
authors.forename: Michael E
authors.initials: ME
authors.lastname: Miller
authors.forename: Rebecca H
authors.initials: RH
authors.lastname: Neiberg
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Marsh
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D015337:Multicenter Studies as Topic; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000628:therapy*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D