title: Do Inactive Older Adults Who Increase Physical Activity Experience Less Disability: Evidence From the Osteoarthritis Initiative.
abstract: BACKGROUND
  Physical inactivity is a leading risk factor for developing disability. Although randomized clinical trials have demonstrated improving physical activity can reduce this risk in older adults with arthritis, these studies did not specifically evaluate inactive adults.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the relationship of changes in physical activity with disability changes among initially inactive adults with or at high risk of knee osteoarthritis from Osteoarthritis Initiative.
  
  
  METHODS
  Inactive persons were identified at baseline based on the US Department of Health and Human Services classification (no [zero] 10-minute session of moderate-to-vigorous [MV] activity over 1 week) from objective accelerometer monitoring. Two years later, physical activity change status was classified as follows: (1) met Federal physical activity guidelines (≥150 MV minutes/week acquired in bouts ≥10 minutes), (2) insufficiently increased activity (some but <150 MV bout minutes/week), or (3) remained inactive. Disability at baseline and 2 years was assessed by Late Life Disability Instrument limitation and frequency scores. Multiple regression evaluated the relationship of physical activity change status with baseline-to-2-year changes in disability scores adjusting for socioeconomics, health factors, and baseline disability score.
  
  
  RESULTS
  Increased physical activity showed a graded relationship with improved disability scores in Late Life Disability Instrument limitation (P < 0.001) and frequency scores (P = 0.027). While increasing MV activity to guideline levels showed the greatest reduction, even insufficiently increased physical activity was related to reduced disability.
  
  
  CONCLUSIONS
  Findings support advice to increase MV physical activity to reduce disability among inactive adults with or at high risk of knee osteoarthritis, even when guidelines are not met.
authors.affiliation: From *Northwestern University Feinberg School of Medicine; †Rehabilitation Institute of Chicago; and ‡Rush University Medical Center, Chicago, IL; §University of Arizona Arthritis Center, Tucson, AZ; and ∥Department of Internal Medicine, Ohio State University, Columbus, OH.
authors.forename: Jing
authors.initials: J
authors.lastname: Song
authors.forename: Abigail L
authors.initials: AL
authors.lastname: Gilbert
authors.forename: Rowland W
authors.initials: RW
authors.lastname: Chang
authors.forename: Christine A
authors.initials: CA
authors.lastname: Pellegrini
authors.forename: Linda S
authors.initials: LS
authors.lastname: Ehrlich-Jones
authors.forename: Jungwha
authors.initials: J
authors.lastname: Lee
authors.forename: Daniel
authors.initials: D
authors.lastname: Pinto
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Semanik
authors.forename: Leena
authors.initials: L
authors.lastname: Sharma
authors.forename: C Kent
authors.initials: CK
authors.lastname: Kwoh
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Jackson
authors.forename: Dorothy D
authors.initials: DD
authors.lastname: Dunlop
mesh_terms: D061725:Accelerometry / Q000379:methods; D000203:Activities of Daily Living; D000368:Aged; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000523:psychology / Q000534:rehabilitation; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation; D063868:Patient Outcome Assessment