Ponderal index

The Ponderal Index (PI) serves as a metric to determine an individual's leanness by juxtaposing their mass with their height. Originally coined as the "Corpulence Index" by Rohrer in 1921, it's also referred to as Rohrer's index.

Historical Context

The inception of the Ponderal Index dates back to 1921, when it was proposed by Rohrer as a measure of corpulence, which is why it bears the alternate moniker, "Corpulence Index" or Rohrer's index.

Comparison to Body Mass Index (BMI)

While both PI and BMI are utilized to assess the proportionality of an individual's mass to their height, they differ in the way the mass is normalized:

• Body Mass Index (BMI): Mass is normalized with the square (second power) of height.
• Ponderal Index (PI): Mass is normalized with the cube (third power) of height.

This distinction allows PI to provide more accurate results for individuals at the extremes of height, namely, the very short and very tall.

Clinical Relevance

Due to its ability to cater to a wider range of heights and thus provide a more precise measure of leanness, the Ponderal Index is most frequently employed in pediatric settings. Notably:

• For infants, the typical PI values are approximately double those of adults. This deviation is largely attributed to the shorter leg proportions seen in infants compared to adults.

Variant Definitions

Though the above formula offers the primary definition of the Ponderal Index, using SI-units (kg for mass and m for height), alternative definitions and units can be encountered in different contexts. When using or referencing PI, it's imperative to ensure the consistency of units and formula application.

See also

• Body mass index
• Waist-to-height ratio

Resources

Latest articles - Ponderal index

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Source: Data courtesy of the U.S. National Library of Medicine. Since the data might have changed, please query MeSH on Ponderal index for any updates.

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