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The Corpulence Index (CI) (also Ponderal Index (PI) or Rohrer's Index) is a measure of corpulence, or of leanness in other variants, 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] [4] and hence is also known as Rohrer's Index. [5] 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. [6] In 2015, Sultan Babar showed that CI does not need to be adjusted for height after adolescence. [4] [6]
with in kilograms and in metres, giving a measure with the same dimensions as density. The corpulence index yields valid results even for very short and very tall persons, [7] 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. [8]
Because of this property, it is most commonly used in pediatrics. [9] [10] (For a baby, one can take crown-heel length for the height. [11] ) 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. [6] It has also been shown to have a lower false positive rate in athletes. [12]
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 | Values considered normal or typical | |
---|---|---|---|
for a 12-month-old infant | beyond infancy | ||
[9] [10] | kg/m3 | 24 [9] | 12 [6] |
[1] [13] | inch * pound -1/3 | 12.49 to 13.92 |
Category | PI (kg/m3 [lower-alpha 1] ) |
---|---|
Underweight | 8-11 |
Normal range | 11-15 |
Overweight | 15-17 |
Obese | >17 |
For infants, units of grams and centimeters are used instead, then the value is multiplied by 100. [17]
Category | PI (child) |
---|---|
Very low | ≤1.12 |
Low | 1.3-1.19 |
Middle | 1.20-1.25 |
Upper middle | 1.26-1.32 |
High | 1.33-1.39 |
Very high | ≥1.40 |
Healthy range | 1.2-1.6 |
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 (kg) and height in metres (m).
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Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. The World Health Organization (WHO) classifies obesity by body mass index (BMI). BMI is further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. In children, a healthy weight varies with age and sex, and obesity determination is in relation to a historical normal group.
Weight management refers to behaviors, techniques, and physiological processes that contribute to a person's ability to attain and maintain a healthy weight. Most weight management techniques encompass long-term lifestyle strategies that promote healthy eating and daily physical activity. Moreover, weight management involves developing meaningful ways to track weight over time and to identify the ideal body weights for different individuals.
Somatotype is a theory proposed in the 1940s by the American psychologist William Herbert Sheldon to categorize the human physique according to the relative contribution of three fundamental elements which he termed somatotypes, classified by him as ectomorphic, mesomorphic, and endomorphic. He created these terms borrowing from the three germ layers of embryonic development: The endoderm,, the mesoderm, and the ectoderm. Later variations of these categories, developed by his original research assistant Barbara Heath, and later by Lindsay Carter and Rob Rempel, are used by academics today.
The body adiposity index (BAI) is a method of estimating the amount of body fat in humans. The BAI is calculated without using body weight, unlike the body mass index (BMI). Instead, it uses the size of the hips compared to the person's height.
A person's waist-to-height ratio (WHtR), occasionally written WtHR or called waist-to-stature ratio (WSR), is defined as their waist circumference divided by their height, both measured in the same units. It is used as a predictor of obesity-related cardiovascular disease. The WHtR is a measure of the distribution of body fat. Higher values of WHtR indicate higher risk of obesity-related cardiovascular diseases; it is correlated with abdominal obesity.
A Body Shape Index (ABSI) or simply body shape index (BSI) is a metric for assessing the health implications of a given human body height, mass and waist circumference (WC). The inclusion of WC is believed to make the BSI a better indicator of risk of mortality from excess weight than the standard body mass index. ABSI correlates only slightly with height, weight and BMI, indicating that it is independent of other anthropometric variables in predicting mortality.
Relative Fat Mass (RFM) is a simple formula for the estimation of overweight or obesity in humans that requires only a calculation based on a ratio of height and waist measurements.
The Metabolic Score for Insulin Resistance (METS-IR) is a metabolic index developed with the aim to quantify peripheral insulin sensitivity in humans; it was first described under the name METS-IR by Bello-Chavolla et al. in 2018. It was developed by the Metabolic Research Disease Unit at the Instituto Nacional de Ciencias Médicas Salvador Zubirán and validated against the euglycemic hyperinsulinemic clamp and the frequently-sampled intravenous glucose tolerance test in Mexican population. It is a non-insulin-based alternative to insulin-based methods to quantify peripheral insulin sensitivity and an alternative to SPINA Carb, the Homeostatic Model Assessment (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI). METS-IR is currently validated for its use to assess cardio-metabolic risk in Latino population.