Ponderal index
The Ponderal Index PI is a measure of leanness of a person[1] calculated as a relationship between mass and height.[2] It was first proposed 1921 as "Corpulence Index" by Rohrer[3]. It is similar to the Body mass index, however the mass is normalized with the third power of body height rather than the second power.
- <math>\mathrm{PI} = \frac{mass}{height^3}</math>
with <math>mass</math> in kg (kilograms) and <math>height</math> in m (meters), giving a measure with the same dimensions as density. The ponderal index yields valid results even for very short and very tall persons [4]. Because of this property, it is most commonly used in pediatrics [5] [6]. The normal values for infants are about twice as high as for adults, which is the result of their relatively short legs.
The ponderal index is variously defined (the first definition should be preferred due to the use of SI-units kg and m) as follows:
| Formula | Units for mass (body weight) |
Units for height (or length) |
Values corresponding to "normal" BMI in a 180 cm tall person |
|---|---|---|---|
| <math>\text{PI}=\frac{mass}{height^3}</math>[6] | kilograms | metres | 10.3 to 13.9, 24 for 12 month old infant[5] |
| <math>\text{PI}=100\frac{mass}{height^3}</math>[5] | grams | centimetres | 2.4 for 12 month old infant |
| <math>\text{PI}=1000\times\frac{\sqrt[3]{mass}}{height}</math>[2] | kilograms | centimetres | 21.75 to 24.0[7] |
| <math>\text{PI}=100\times\frac{\sqrt[3]{mass}}{height}</math>[8] | kilograms | centimetres | 2.175 to 2.4 |
| <math>\text{PI}=\frac{height}{\sqrt[3]{mass}}</math>[1] | pounds | inches | 12.49 to 13.92 |
Excel formula for Ponderal Index
Fx= weight[kg] / (POWER(height[cm] , 3) / 1000000)
See also
References
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<references />, or <references group="..." />External links
- Online Ponderal Index Calculator, which uses the first definition.
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- ↑ Jump up to: 1.0 1.1 Foods and Nutrition Encyclopedia, Audrey H. Ensminger, Marion Eugene Ensminger. p. 1645
- ↑ Jump up to: 2.0 2.1 EXSS 323: LAB 1 - BIOMECHANICS TOOLS: Computers, Algebra and Trig Oregon State University
- Jump up ↑ F. Rohrer: "Der Index der Körperfülle als Maß des Ernährungszustandes" (engl: The index of corpulence as measure of nutritional state), Münchner Med. Wschr. 68(1921), 580-582
- Jump up ↑ Lawrence F. Ditmier: New Developments in Obesity Research. Nova Science Publishers, Hauppauge, New York 2006, ISBN 1-60021-296-4
- ↑ Jump up to: 5.0 5.1 5.2 D. P. Davies: "Size at birth and growth in the first year of life of babies who are overweight and underweight at birth", Proc. Nutr. Soc. 39(1980),25-33
- ↑ Jump up to: 6.0 6.1 ACC/SCN NUTRITION POLICY PAPER No. 19 - Glossary by Lindsay H. Allen and Stuart R. Gillespie
- Jump up ↑ The source quoted (Oregon State University) states that typical healthy PI values range between 20 and 25.
- Jump up ↑ Medical Dictionary University of Newcastle upon Tyne
