# Corpulence index

(Redirected from Rohrer's index)

The Corpulence Index (CI) or Ponderal Index (PI) is a measure of leanness (corpulence) of a person[1] calculated as a relationship between mass and height.[2] It was first proposed in 1921 as the "Corpulence measure" by Swiss physician Fritz Rohrer[3] and hence is also known as Rohrer's Index.[4] 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.[5]

${\displaystyle \mathrm {CI} ={\frac {mass}{height^{3}}}}$

For a baby, it is calculated as

${\displaystyle \mathrm {CI} ={\frac {birthweight}{Crown-heel-length^{3}}}}$[6]

with ${\displaystyle mass}$ in kilograms and ${\displaystyle height}$ in meters, giving a measure with the same dimensions as density. The corpulence index yields valid results even for very short and very tall persons.[7] Because of this property, it is most commonly used in pediatrics.[8][9] The normal values for infants are about twice as high as for adults, which is the result of their relatively short legs.[citation needed] It does not need to be adjusted for age after adolescence.[5] It has also been shown to have a lower false positive rate in athletes.[10]

The corpulence 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
${\displaystyle {\text{CI}}={\frac {mass}{height^{3}}}}$[9] kilograms metres 10.3 to 13.9, 24 for 12-month-old infant[8] ~12 for those 12-year-old or older.[5]
${\displaystyle {\text{CI}}=1000{\frac {mass}{height^{3}}}}$[8] grams centimetres 2.4 for 12-month-old infant
${\displaystyle {\text{CI}}=1000\times {\frac {\sqrt[{3}]{mass}}{height}}}$[2] kilograms centimetres 21.75 to 24.0[11]
${\displaystyle {\text{CI}}=100\times {\frac {\sqrt[{3}]{mass}}{height}}}$[12] kilograms centimetres 2.175 to 2.4
${\displaystyle {\text{CI}}={\frac {height}{\sqrt[{3}]{mass}}}}$[1] pounds inches 12.49 to 13.92

## References

1. ^ a b Foods and Nutrition Encyclopedia, Audrey H. Ensminger, Marion Eugene Ensminger. p. 1645
2. ^ a b EXSS 323: LAB 1 - BIOMECHANICS TOOLS: Computers, Algebra and Trig Oregon State University
3. ^ F. Rohrer (1921). "Der Index der Körperfülle als Maß des Ernährungszustandes". Münchner Med. Wschr. 68: 580–582.
4. ^ http://www.wisegeek.com/what-is-the-ponderal-index.htm
5. ^ a b c d Babar, Sultan (March 2015). "Evaluating the Performance of 4 Indices in Determining Adiposity". Clinical Journal of Sports Medicine. Lippincott Williams & Wilkins). 25 (2): 183. Retrieved August 2015. Check date values in: |access-date= (help)
6. ^ Fayyaz, Jabeen (June 2005). "Ponderal Index". Journal of Pakistan Medical Association.
7. ^ Lawrence F. Ditmier: New Developments in Obesity Research. Nova Science Publishers, Hauppauge, New York 2006, ISBN 1-60021-296-4[page needed]
8. ^ a b c 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. PMID 6988835. doi:10.1079/PNS19800005.
9. ^ a b ACC/SCN NUTRITION POLICY PAPER No. 19 - Glossary Archived 2007-08-20 at the Wayback Machine. by Lindsay H. Allen and Stuart R. Gillespie
10. ^ Babar, Sultan (March 2016). "The Use of Adiposity Indices for Wide Receivers From 2015 NFL Combine". Clinical Journal of Sports Medicine. Lippincott Williams & Wilkins) 2. 26 (2): e23. Retrieved April 2016. Check date values in: |access-date= (help)
11. ^ The source quoted (Oregon State University) states that typical healthy PI values range between 20 and 25.
12. ^ Medical Dictionary University of Newcastle upon Tyne
13. ^ 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.