A Better Index of Body Adiposity

Authors

  • Richard N. Bergman,

    1. Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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  • Darko Stefanovski,

    1. Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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  • Thomas A. Buchanan,

    1. Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
    2. Department of Ob/Gyn and Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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  • Anne E. Sumner,

    1. Clinical and Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health, Bethesda, Maryland, USA
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  • James C. Reynolds,

    1. Department of Radiology and Imaging Sciences, Nuclear Medicine, National Institutes of Health, Bethesda, Maryland, USA
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  • Nancy G. Sebring,

    1. Nutrition, National Institutes of Health, Bethesda, Maryland, USA
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  • Anny H. Xiang,

    1. Department of Research and Evaluation, Kaiser Permanente Southern California Medical Group, Pasadena, California, USA
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  • Richard M. Watanabe

    Corresponding author
    1. Department of Preventive Medicine, Division of Biostatistics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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(rbergman@usc.edu)

Abstract

Obesity is a growing problem in the United States and throughout the world. It is a risk factor for many chronic diseases. The BMI has been used to assess body fat for almost 200 years. BMI is known to be of limited accuracy, and is different for males and females with similar %body adiposity. Here, we define an alternative parameter, the body adiposity index (BAI = ((hip circumference)/((height)1.5)–18)). The BAI can be used to reflect %body fat for adult men and women of differing ethnicities without numerical correction. We used a population study, the “BetaGene” study, to develop the new index of body adiposity. %Body fat, as measured by the dual-energy X-ray absorptiometry (DXA), was used as a “gold standard” for validation. Hip circumference (R = 0.602) and height (R = −0.524) are strongly correlated with %body fat and therefore chosen as principal anthropometric measures on which we base BAI. The BAI measure was validated in the “Triglyceride and Cardiovascular Risk in African-Americans (TARA)” study of African Americans. Correlation between DXA-derived %adiposity and the BAI was R = 0.85 for TARA with a concordance of C_b = 0.95. BAI can be measured without weighing, which may render it useful in settings where measuring accurate body weight is problematic. In summary, we have defined a new parameter, the BAI, which can be calculated from hip circumference and height only. It can be used in the clinical setting even in remote locations with very limited access to reliable scales. The BAI estimates %adiposity directly.

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