title: Lower extremity strength, systemic inflammation and all-cause mortality: Application to the "fat but fit" paradigm using cross-sectional and longitudinal designs.
abstract: BACKGROUND
  No study has applied the "fat-but-fit" paradigm with respect to muscular strength as an index of fitness, despite muscular strength being independently associated with functional ability and mortality.
  
  
  OBJECTIVE
  To examine the relationship between lower extremity muscular strength, C-reactive protein (CRP), and all-cause mortality among normal weight, overweight and obese individuals.
  
  
  METHODS
  Data from the 1999-2002 NHANES were used (N=2740 adults; ≥ 50 years). CRP values were obtained from a blood sample. Lower body isokinetic knee extensor strength (IKES) was assessed using a Kin Kom MP isokinetic dynamometer. Participant data was linked to death certificate data from the National Death Index to ascertain all-cause mortality status. Participants were classified, based on body mass index (BMI) and strength as: normal weight and unfit (<75th IKES percentile); overweight and unfit; obese and unfit: normal weight and fit (≥ 75th IKES percentile); overweight and fit; and obese and fit.
  
  
  RESULTS
  Independent of physical activity and other confounders, compared to those who were normal weight and unfit, unfit overweight (β=.14, p=0.009), unfit obese (β=.33, p<0.001), and obese and fit (β=.17, p=0.008) participants, had higher CRP levels. However, there was no difference in CRP levels between normal weight and unfit participants and overweight and fit participants (β=0.04, p=0.35). Compared to normal weight unfit adults, overweight fit (HR=0.28; 95% CI: 0.11-0.70; p=0.008) adults had a lower hazard rate for all-cause mortality.
  
  
  CONCLUSIONS
  These finding suggest that increased lower body strength, independent of physical activity, may reduce premature all-cause mortality and attenuate systemic inflammation among overweight adults.
authors.affiliation: Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, University, MS, United States.
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Buckner
authors.affiliation: Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, University, MS, United States.
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Loenneke
authors.affiliation: Department of Health, Exercise Science and Recreation Management, Center for Health Behavior Research, The University of Mississippi, University, MS, United States. Electronic address: pdloprin@olemiss.edu.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Loprinzi
mesh_terms: D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D009749:Nutrition Surveys; D009765:Obesity / Q000097:blood / Q000503:physiopathology / Q000534:rehabilitation; D050177:Overweight / Q000097:blood / Q000503:physiopathology / Q000534:rehabilitation; D012189:Retrospective Studies
chemical_list: D002097:C-Reactive Protein
keywords: Epidemiology; Fat-but-fit; Inflammation; Muscular strength