The Corpulence Index (CI) (also Ponderal Index (PI) or Rohrer's Index) is a measure of

corpulence Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...

, or of leanness in other variants, of a person''Foods and Nutrition Encyclopedia'', Audrey H. Ensminger, Marion Eugene Ensminger. p. 1645 calculated as a relationship between mass and height.EXSS 323: LAB 1 - BIOMECHANICS TOOLS: Computers, Algebra and Trig
Oregon State University It was first proposed in 1921 as the "Corpulence measure" by Swiss physician

Fritz Rohrer Fritz Rohrer (1888–1926) was a Swiss physician, specialised in respiratory physiology. In 1915 he published an analysis of the flow of air in the human lung and its relationship to pressure, based on detailed measurements of the pulmonary airways ...

and hence is also known as Rohrer's Index. It is similar to the

body mass index Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...

, but the mass is normalized with the third power of body height rather than the second power. In 2015, Sultan Babar showed that CI does not need to be adjusted for height after adolescence. :

\mathrm = \frac

with

\mathrm

in kilograms and

\mathrm

in metres, giving a measure with the same

dimensions In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordina ...

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

. The corpulence index yields valid results even for very short and very tall persons, which is a problem with BMI — for example, an ideal body weight for a person 152.4 cm tall (48 kg) will render BMI of 20.7 and CI of 13.6, while for a person 200 cm tall (99 kg), the BMI will be 24.8, very close to the "overweight" threshold of 25, while CI will be 12.4. Because of this property, it is most commonly used in

pediatrics Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until th ...

.ACC/SCN NUTRITION POLICY PAPER No. 19 - Glossary
by Lindsay H. Allen and Stuart R. Gillespie (For a baby, one can take crown-heel length for the height.) The normal values for infants are about twice as high as for adults, which is the result of their relatively short legs. It does not need to be adjusted for age after adolescence. It has also been shown to have a lower false positive rate in athletes. The corpulence index is variously defined (the first definition should be preferred due to the use of SI-units kg and m) as follows:

Significance

* It plays a role in assessing whether the

intrauterine growth restriction Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's ...

of a child is symmetrical or asymmetrical. * CI has been shown to have higher sensitivity, specificity, and

positive and negative predictive values The positive and negative predictive values (PPV and NPV respectively) are the proportions of positive and negative results in statistics and diagnostic tests that are true positive and true negative results, respectively. The PPV and NPV descr ...

than

for determining

adiposity Adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular en ...

. * It is used to calculate ''ectomorphy'' in the Heath–Carter formula.

References

{{reflist

External links

Online Ponderal Index Calculator
which uses the first definition.
Ponderal Index Calculator
which uses metric values. (German site)
Android App for Corpulence Index

Apple app for Corpulence Index
Medical terminology Body shape Classification of obesity Human body weight Pediatrics

Significance

See also

References

External links