title: Body Mass Index, the Most Widely Used But Also Widely Criticized Index: Would a Criterion Standard Measure of Total Body Fat Be a Better Predictor of Cardiovascular Disease Mortality?
abstract: OBJECTIVE
  To examine whether an accurate measure (using a criterion standard method) of total body fat would be a better predictor of cardiovascular disease (CVD) mortality than body mass index (BMI).
  
  
  METHODS
  A total of 60,335 participants were examined between January 1, 1979, and December 31, 2003, and then followed-up for a mean follow-up period of 15.2 years. Body mass index was estimated using standard procedures. Body composition indices (ie, body fat percentage [BF%], fat mass index [FMI], fat-free mass [FFM], and FFM index [FFMI]) were derived from either skinfold thicknesses or hydrostatic weighing. For exact comparisons, the indices studied were categorized identically using sex-specific percentiles.
  
  
  RESULTS
  Compared with a medium BMI, a very high BMI was associated with a hazard ratio (HR) of 2.7 (95% CI, 2.1-3.3) for CVD mortality, which was a stronger association than for BF% or FMI (ie, HR, 1.6; 95% CI, 1.3-1.9 and HR, 2.2; 95% CI, 1.8-2.7, respectively). Compared with a medium FFMI, a very high FFMI was associated with an HR of 2.2 (95% CI, 1.7-2.7) for CVD mortality, with these estimates being markedly smaller for FFM (ie, HR, 1.2; 95% CI, 0.9-1.6). When the analyses were restricted only to the sample assessed with hydrostatic weighing (N=29,959, 51.7%), the results were similar, with even slightly larger differences in favor of BMI (ie, HR, 3.0; 95% CI, 2.2-4.0) compared with BF% and FMI (ie, HR, 1.5; 95% CI, 1.2-1.9 and HR, 2.1; 95% CI, 1.6-2.7, respectively). We estimated Harrell's c-index as an indicator of discriminating/predictive ability of these models and observed that the c-index for models including BMI was significantly higher than that for models including BF% or FMI (P<.005 for all).
  
  
  CONCLUSIONS
  The simple and inexpensive measure of BMI can be as clinically important as, or even more than, total adiposity measures assessed using accurate, complex, and expensive methods. Physiological explanations for these findings are discussed.
authors.affiliation: PROFITH "PROmoting FITness and Health through physical activity" Research Group, Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada, Granada, Spain; Department of Biosciences and Nutrition at NOVUM, Karolinska Institutet, Huddinge, Sweden. Electronic address: ortegaf@ugr.es.
authors.forename: Francisco B
authors.initials: FB
authors.lastname: Ortega
authors.affiliation: Department of Exercise Science, University of South Carolina, Columbia.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Sui
authors.affiliation: Department of Cardiovascular Diseases, John Ochsner Heart and Vascular Institute, Ochsner Clinical School, The University of Queensland School of Medicine, New Orleans, LA.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Lavie
authors.affiliation: Department of Exercise Science, University of South Carolina, Columbia; Department of Epidemiology and Biostatistics, University of South Carolina, Columbia.
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D050154:Adiposity / Q000502:physiology*; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000401:mortality*; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests
chemical_list: D008055:Lipids