No apparent progress in bioelectrical impedance accuracy: validation against metabolic risk and DXA

Obesity (Silver Spring). 2009 Jan;17(1):183-7. doi: 10.1038/oby.2008.474. Epub 2008 Nov 6.

Abstract

Bioelectrical impedance (BIA) is quick, easy, and safe when quantifying fat and lean tissue. New BIA models (Tanita BC-418 MA, abbreviated BIA(8)) can perform segmental body composition analysis, e.g., estimate %trunkal fatness (%TF). It is not known, however, whether new BIA models can detect metabolic risk factors (MRFs) better than older models (Tanita TBF-300, abbreviated BIA(4)). We therefore tested the correlation between MRF and percentage whole-body fat (%BF) from BIA(4) and BIA(8) and compared these with the correlation between MRF and dual-energy X-ray absorptiometry (DXA, used as gold standard), BMI and waist circumference (WC). The sample consisted of 136 abdominally obese (WC >or= 88 cm), middle-aged (30-60 years) women. MRF included fasting blood glucose and insulin; high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides; high sensitive C-reactive protein, plasminogen activator inhibitor-1 (PAI-1), and fibrinogen; and alanine transaminase (ALT) liver enzyme. We found that similar to DXA, but in contrast to BMI, neither %BF BIA(4) nor %BF BIA(8) correlated with blood lipids or ALT. In the segmental analysis of %TF, BIA(8) only correlated with inflammatory markers, but not insulin, blood lipids, or ALT liver enzyme (in contrast to WC and %TF DXA). %TF DXA was associated with homeostatic model assessment insulin resistance (HOMA-IR) independently of WC (P = 0.03), whereas %TF BIA(8) was not (P = 0.53). Receiver-operating characteristic (ROC) curves confirmed that %TF BIA(8) did not differ from chance in the detection of insulin resistance (P = 0.26). BIA estimates of fatness were, at best, weakly correlated with obesity-related risk factors in abdominally obese women, even the new eight-electrode model. Our data support the continued use of WC and BMI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon*
  • Adipose Tissue / anatomy & histology*
  • Adult
  • Alanine Transaminase / blood
  • Body Mass Index
  • C-Reactive Protein / analysis
  • Electric Impedance*
  • Exercise
  • Humans
  • Insulin / blood
  • Insulin Resistance*
  • Lipids / blood
  • Middle Aged
  • Plasminogen Activator Inhibitor 1 / blood
  • Reproducibility of Results
  • Waist Circumference

Substances

  • Insulin
  • Lipids
  • Plasminogen Activator Inhibitor 1
  • C-Reactive Protein
  • Alanine Transaminase