The Ponderal Index (PI) is a measure of leanness of a person calculated as a relationship between mass and height. It was first proposed in 1921 as the "Corpulence Index" by Rohrer and hence also known as Rohrer's index. It is similar to the body mass index, but the mass is normalized with the third power of body height rather than the second power.
For a baby, it is calculated as
with in kg (kilograms) and 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. Because of this property, it is most commonly used in pediatrics. 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
|Units for height
|Values corresponding to "normal"
BMI in a 180 cm tall person
|||kilograms||metres||10.3 to 13.9, 24 for 12 month old infant|
|||grams||centimetres||2.4 for 12 month old infant|
|||kilograms||centimetres||21.75 to 24.0|
|||kilograms||centimetres||2.175 to 2.4|
|||pounds||inches||12.49 to 13.92|
- It plays a role in assessing whether a the intrauterine growth restriction of a child is symmetrical or asymmetrical.
- Body adiposity index
- Foods and Nutrition Encyclopedia, Audrey H. Ensminger, Marion Eugene Ensminger. p. 1645
- EXSS 323: LAB 1 - BIOMECHANICS TOOLS: Computers, Algebra and Trig Oregon State University
- Fayyaz, Jabeen (June 2005). "Ponderal Index". Journal of Pakistan Medical Association.
- Lawrence F. Ditmier: New Developments in Obesity Research. Nova Science Publishers, Hauppauge, New York 2006, ISBN 1-60021-296-4[page needed]
- Davies, D. P. (1980). "Size at birth and growth in the first year of life of babies who are overweight and underweight at birth". Proceedings of the Nutrition Society 39 (1): 25–33. doi:10.1079/PNS19800005. PMID 6988835.
- ACC/SCN NUTRITION POLICY PAPER No. 19 - Glossary by Lindsay H. Allen and Stuart R. Gillespie
- The source quoted (Oregon State University) states that typical healthy PI values range between 20 and 25.
- Medical Dictionary University of Newcastle upon Tyne
- Khoury, MJ; Berg, CJ; Calle, EE (September 1990). "The ponderal index in term newborn siblings.". American journal of epidemiology 132 (3): 576–83. PMID 2389761.
- Online Ponderal Index Calculator, which uses the first definition.
- Ponderal Index Calculator, which uses metric values. (German site)
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