O'Connor et al developed equations for estimating percent body fat in young adults as determined by DXA. The equations allow better estimates in different racial groups. The authors are fro the Texas Obesity Research Center, University of Houston, University of Alabamda at Birmingham and Baylor College of Medicine.
Patient selection: college-age students < 35 years of age
Skinfold measurements were taken at the same sites as used by Jackson and Pollock (see above).
Measurements taken in women:
(1) body mass index (BMI) based on height and weight
(2) skinfold thickness in mm on the triceps on one side
(3) skinfold thickness in mm on the iliac crest on one side
(4) skinfold thickness in mm on the thigh on one side
cumulative skinfold thickness in mm =
= SUM(skinfold thicknesses at triceps, iliac crest, thigh)
percent body fat by DXA =
= (core equation) + (racial constant)
core equation using cumulative skinfold thickness =
= (-0.0011 * ((cumulative skinfold)^2)) + (0.387 * (cumulative skinfold))
core equation using cumulative skinfold thickness and BMI =
= (-0.0007 * ((cumulative skinfold)^2)) + (0.169 * (cumulative skinfold)) + (0.849 * (BMI))
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Racial Group
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Racial Constant for Skinfold Equation
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Racial Constant for Skinfold and BMI
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non-Hispanic White
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8.34
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1.26
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Hispanic
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8.32
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3.15
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African American
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10.86
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-0.08
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Limitations:
• Asians are not included in the diverse population.
• Accurate measurements of skinfold thickness is essential.
