title: Body Mass Index Underestimates Adiposity in Persons With Multiple Sclerosis.
abstract: OBJECTIVE
  To examine the relation between body mass index (BMI) and adiposity assessed by dual-energy x-ray absorptiometry in persons with multiple sclerosis (MS) and non-MS controls as well as to determine the accuracy of standard and alternate BMI thresholds for obesity.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  The sample included persons with MS (n=235) and controls (n=53) (N=288).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Main outcome measures included BMI, whole body soft tissue composition (ie, percent body fat [%BF], fat mass, and lean soft tissue mass), bone mineral content, and bone mineral density.
  
  
  RESULTS
  We observed significant strong associations between BMI and sex-specific %BF in persons with MS and non-MS controls, and BMI explained ∼40% of the variance in %BF in both MS and control samples. Receiver operating characteristic curve analyses indicated that the standard BMI threshold for obesity (ie, 30kg/m(2)) had excellent specificity (93%-100%) but poor sensitivity (37%-44%) in persons with MS and non-MS controls. The BMI threshold that best identified %BF-defined obesity was 24.7kg/m(2) in the MS sample and 25.1kg/m(2) in the control sample.
  
  
  CONCLUSIONS
  We determined a strong association between BMI and adiposity; however, the current BMI threshold for classifying obesity underestimates true adiposity in persons with MS. A similar relation was observed between BMI and obesity in non-MS controls. The non-MS sample included primarily middle-aged women, and similar BMI-%BF misclassifications have been reported in these samples.
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL. Electronic address: lpilutti@illinois.edu.
authors.forename: Lara A
authors.initials: LA
authors.lastname: Pilutti
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Motl
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity; D000293:Adolescent; D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D015519:Bone Density; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D012680:Sensitivity and Specificity
keywords: Body composition; Body mass index; Multiple sclerosis; Obesity; Rehabilitation