title: 25-hydroxyvitamin D status and change in physical performance and strength in older adults: the Health, Aging, and Body Composition Study.
abstract: Low 25-hydroxyvitamin D (25(OH)D) concentrations are common among older adults and are associated with poorer physical performance and strength, but results from longitudinal studies have been inconsistent. The 25(OH)D threshold for physical performance and strength was determined, and both cross-sectional and longitudinal associations between 25(OH)D and physical performance and strength were examined, in men and women aged 71-80 years from the Health, Aging, and Body Composition Study (n = 2,641). Baseline serum 25(OH)D was measured in 1998-1999, and physical performance and strength were measured at baseline and at 2- and 4-year follow-up. Piecewise regression models were used to determine 25(OH)D thresholds. Linear regression and mixed models were used to examine cross-sectional and longitudinal associations. The 25(OH)D thresholds were 70-80 nmol/L for physical performance and 55-70 nmol/L for strength. Participants with 25(OH)D <50 nmol/L had poorer physical performance at baseline and at 2- and 4-year follow-up than participants with 25(OH)D ≥75 nmol/L (P < 0.01). Although physical performance and strength declined over 4 years of follow-up (P < 0.0001), in general, the rate of decline was not associated with baseline 25(OH)D. Older adults with low 25(OH)D concentrations had poorer physical performance over 4 years of follow-up, but low 25(OH)D concentrations were not associated with a faster rate of decline in physical performance or strength.
authors.affiliation: Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157-1207, USA. dhouston@wakehealth.edu
authors.forename: Denise K
authors.initials: DK
authors.lastname: Houston
authors.forename: Janet A
authors.initials: JA
authors.lastname: Tooze
authors.forename: Rebecca H
authors.initials: RH
authors.lastname: Neiberg
authors.forename: Dorothy B
authors.initials: DB
authors.lastname: Hausman
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Johnson
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Doug C
authors.initials: DC
authors.lastname: Bauer
authors.forename: Peggy M
authors.initials: PM
authors.lastname: Cawthon
authors.forename: M Kyla
authors.initials: MK
authors.lastname: Shea
authors.forename: Gary G
authors.initials: GG
authors.lastname: Schwartz
authors.forename: Jeff D
authors.initials: JD
authors.lastname: Williamson
authors.forename: Frances A
authors.initials: FA
authors.lastname: Tylavsky
authors.forename: Marjolein
authors.initials: M
authors.lastname: Visser
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D016009:Chi-Square Distribution; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D010147:Pain Measurement; D010414:Pennsylvania; D010809:Physical Fitness / Q000502:physiology*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013714:Tennessee; D014505:Urban Population; D014808:Vitamin D Deficiency / Q000097:blood*