title: Dynapenic obesity and the effect on long-term physical function and quality of life: data from the osteoarthritis initiative.
abstract: BACKGROUND
  Obesity is associated with functional impairment, institutionalization, and increased mortality risk in elders. Dynapenia is defined as reduced muscle strength and is a known independent predictor of adverse events and disability. The synergy between dynapenia and obesity leads to worse outcomes than either independently. We identified the impact of dynapenic obesity in a cohort at risk for and with knee osteoarthritis on function.
  
  
  METHODS
  We identified adults aged ≥ 60 years from the Osteoarthritis Initiative. Obesity was defined as a body mass index ≥ 30 kg/m(2). Dynapenia was classified using the lowest sex-specific tertile of knee extensor strength. Participants were grouped according to obesity and knee strength: dynapenic obesity; dynapenia without obesity; obesity without dynapenia; and no dynapenia nor obesity. Four-year data was available. Self-reported activities of daily living (ADL) were assessed at follow-up. Outcomes of gait speed, 400 m walk distance, Late-life Disability and Function Index (LLFDI), and Short-Form (SF)-12 were analyzed using mixed effects and logistic regression models.
  
  
  RESULTS
  Of 2025 subjects (56.3 % female), mean age was 68.2 years and 182 (24.1 %) had dynapenic obesity. Dynapenic obesity was associated with reduced gait speed, LLFDI-limitations, and SF-12 physical score in both sexes and in the 400 m walk in men only (all p < 0.001). A time*group interaction was significant for dynapenic obese men in the 400 m walk distance only. Odds of ADL limitations in dynapenic obesity was OR 2.23 [1.42:3.50], in dynapenia 0.98 [0.66:1.46], and in obesity 1.98 [1.39:2.80] in males. In females, odds were 2.45 [1.63:3.68], 1.60 [1.15:2.22], and 1.47 [1.06:2.04] respectively.
  
  
  CONCLUSIONS
  Dynapenic obesity may be a risk factor for functional decline suggesting the need to target subjects with low knee strength and obesity.
authors.affiliation: Section of General Internal Medicine, Dartmouth-Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, NH, 03756, USA. john.batsis@gmail.com.|Centers for Health and Aging, Dartmouth College, Lebanon, NH, 03756, USA. john.batsis@gmail.com.|Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA. john.batsis@gmail.com.|Dartmouth Weight and Wellness Center, Lebanon, NH, 03756, USA. john.batsis@gmail.com.|Health Promotion Research Center at Dartmouth, Lebanon, NH, 03756, USA. john.batsis@gmail.com.|The Dartmouth Institute for Health Policy & Clinical Practice, Dartmouth College, Hanover, NH, 03756, USA. john.batsis@gmail.com.
authors.forename: John A
authors.initials: JA
authors.lastname: Batsis
authors.affiliation: Centers for Health and Aging, Dartmouth College, Lebanon, NH, 03756, USA. Alicia.J.Zbehlik@hitchcock.org.|Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA. Alicia.J.Zbehlik@hitchcock.org.|The Dartmouth Institute for Health Policy & Clinical Practice, Dartmouth College, Hanover, NH, 03756, USA. Alicia.J.Zbehlik@hitchcock.org.|Section of Rheumatology, Dartmouth-Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, NH, 03756, USA. Alicia.J.Zbehlik@hitchcock.org.
authors.forename: Alicia J
authors.initials: AJ
authors.lastname: Zbehlik
authors.affiliation: Department of Rehabilitation, Lebanon, NH, 03756, USA. dawna.pidgeon@hitchcock.org.
authors.forename: Dawna
authors.initials: D
authors.lastname: Pidgeon
authors.affiliation: Centers for Health and Aging, Dartmouth College, Lebanon, NH, 03756, USA. Stephen.J.Bartels@dartmouth.edu.|Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA. Stephen.J.Bartels@dartmouth.edu.|Dartmouth Weight and Wellness Center, Lebanon, NH, 03756, USA. Stephen.J.Bartels@dartmouth.edu.|Health Promotion Research Center at Dartmouth, Lebanon, NH, 03756, USA. Stephen.J.Bartels@dartmouth.edu.|The Dartmouth Institute for Health Policy & Clinical Practice, Dartmouth College, Hanover, NH, 03756, USA. Stephen.J.Bartels@dartmouth.edu.|Department of Community and Family Medicine, Lebanon, NH, 03756, USA. Stephen.J.Bartels@dartmouth.edu.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Bartels
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D010003:Osteoarthritis / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D011446:Prospective Studies; D011788:Quality of Life; D012307:Risk Factors; D013223:Statistics as Topic; D013997:Time Factors