Difference between revisions of "Healthy reference population"
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|info=[[Body mass excess]] | |info=[[Body mass excess]] | ||
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''Work in progress'' by [[Gnaiger E]] 2020-01- | ''Work in progress'' by [[Gnaiger E]] 2020-01-19 linked to a preprint in preparation on [[body mass excess |'''body mass excess, BME''']]. | ||
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== From BMI to BME == | == From BMI to BME == | ||
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:::: The HRP is characterized by three allometric phases in childhood to early adolescence (up to 1.26 m height), and a final phase with an exponent of 2.867 (=1/0.35) at heights above 1.26 m, equal in women and men (Fig. 1; green line for ''M''° at BME=0). | :::: The HRP is characterized by three allometric phases in childhood to early adolescence (up to 1.26 m height), and a final phase with an exponent of 2.867 (=1/0.35) at heights above 1.26 m, equal in women and men (Fig. 1; green line for ''M''° at BME=0). | ||
:::::::: '''Figure 1''': Four phases of the allometric relationship between [[body mass]], ''M''°, and height, ''H'', in the healthy reference population (HRP), and shift of ''M'' at [[body mass excess]], BME, indicating underweight (BME = -0.2 and -0.1) or overweight (BME = 0.2) and increasing degrees of obesity (0.4 to 1.0). | :::::::: '''Figure 1''': Four phases of the allometric relationship between [[body mass]], ''M''°, and height, ''H'', in the healthy reference population (HRP), and shift of ''M'' at [[body mass excess]], BME, indicating underweight (BME = -0.2 and -0.1) or overweight (BME = 0.2) and increasing degrees of obesity (BME = 0.4 to 1.0). | ||
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< | :::: At any given height, the personal body mass may deviate from the reference body mass, ''M''°, in the HRP for the same height. This difference is the excess body mass, ''M''<sub>E</sub> = ''M''-''M''°, is normalized for ''M''°, we obtain the simple definition of the [[body mass excess]], BME = ''M''<sub>E</sub>/''M''°. By this definition, the BME equals zero in the HRP at all heights. For comparison, it is instructive to calculated the BMI as a function of height in the HRP, defining this as the BMI° or ''precision BMI'' at BME=0. The normal BMI of 20 kg·m<sup>-2</sup> is obtained in the HRP at ''H''=1.7 m and ''M''°=57.7 kg/x. If this normal BMI would represent a general index independent of height, it should be constant for the HRP, which is clearly not the case, neither for adults nor children (Fig. 2). | ||
[[File:HRP-BMI.png|400px|right]] | |||
:::::::: '''Figure 2''': Precision reference body mass index, BMI°, with the BMI°=20 kg·m<sup>-2</sup> at the height of 1.70 m in the healthy reference population (dashed lines). The circle marks the harmonization point between the BMI of 20 kg·m<sup>-2</sup> (normal) and the precision BMI°. For persons smaller than 1.7 m, the BMI° is below 20 kg·m<sup>-2</sup>, such that a BMI of 17.9 instead of 20 kg·m<sup>-2</sup> is the precision reference at a height of 1.5 m. On the other hand, at a height of 1.9 m a BMI of 22 instead of 20 kg·m<sup>-2</sup> is the precision reference (dotted lines). | |||
:::: The concept of body mass excess, BME, is simple and easy to communicate to the general public. In contrast, neither the BMI nor the concept of a precision BMI can be explained easily. With the BMI firmly established by convention in the WHO, however, it is important to harmonize the concepts of BME and BMI. Fig. 2 provides the first step for harmonization by assigning to the height of 'reference man' ([[Sender 2016 PLOS Biol]]) the BMI of 20 kg·m<sup>-2</sup> as BMI°. [[BME cutoff points]] for overweight and obese are then obtained for BMI cutoffs of 25 and 30 kg·m<sup>-2</sup> at heights of 1.79 and 1.85 m, respectively. | |||
::::» Further details: [[BME cutoff points]]). | |||
== MitoPedia: BME == | == MitoPedia: BME == |
Revision as of 13:37, 19 January 2020
Description
A healthy reference population, HRP, of zero underweight or overweight is considered as a standard population. The WHO Child Growth Standards on height and body mass are based on large samples in longitudinal (N=1737 children) and cross-sectional studies (N=6669) with similar numbers of girls and boys from Brazil, Ghana, India, Norway, Oman and the USA (1997-2003). Anthropometric studies carried out on adults since the 1960ies are prone to reflect the impact of high-caloric nutrition on allometric relationships, referring us to earlier time points for a HRP. The Committee on Biological Handbooks compiled a large dataset on height and body mass of healthy males from infancy to old age (CBH dataset, N=17523; Zucker 1962). The original studies were published between 1931 and 1944 and thus apply to a population (USA) before emergence of the fast-food and soft drink epidemic, and with a lifestyle demanding a balanced physical activity without the impact of local war or economic disaster on starvation.
Abbreviation: HRP
Reference: Body mass excess
Work in progress by Gnaiger E 2020-01-19 linked to a preprint in preparation on body mass excess, BME.
From BMI to BME
Four allometric phases
- The HRP is characterized by three allometric phases in childhood to early adolescence (up to 1.26 m height), and a final phase with an exponent of 2.867 (=1/0.35) at heights above 1.26 m, equal in women and men (Fig. 1; green line for M° at BME=0).
- Figure 1: Four phases of the allometric relationship between body mass, M°, and height, H, in the healthy reference population (HRP), and shift of M at body mass excess, BME, indicating underweight (BME = -0.2 and -0.1) or overweight (BME = 0.2) and increasing degrees of obesity (BME = 0.4 to 1.0).
- At any given height, the personal body mass may deviate from the reference body mass, M°, in the HRP for the same height. This difference is the excess body mass, ME = M-M°, is normalized for M°, we obtain the simple definition of the body mass excess, BME = ME/M°. By this definition, the BME equals zero in the HRP at all heights. For comparison, it is instructive to calculated the BMI as a function of height in the HRP, defining this as the BMI° or precision BMI at BME=0. The normal BMI of 20 kg·m-2 is obtained in the HRP at H=1.7 m and M°=57.7 kg/x. If this normal BMI would represent a general index independent of height, it should be constant for the HRP, which is clearly not the case, neither for adults nor children (Fig. 2).
- Figure 2: Precision reference body mass index, BMI°, with the BMI°=20 kg·m-2 at the height of 1.70 m in the healthy reference population (dashed lines). The circle marks the harmonization point between the BMI of 20 kg·m-2 (normal) and the precision BMI°. For persons smaller than 1.7 m, the BMI° is below 20 kg·m-2, such that a BMI of 17.9 instead of 20 kg·m-2 is the precision reference at a height of 1.5 m. On the other hand, at a height of 1.9 m a BMI of 22 instead of 20 kg·m-2 is the precision reference (dotted lines).
- The concept of body mass excess, BME, is simple and easy to communicate to the general public. In contrast, neither the BMI nor the concept of a precision BMI can be explained easily. With the BMI firmly established by convention in the WHO, however, it is important to harmonize the concepts of BME and BMI. Fig. 2 provides the first step for harmonization by assigning to the height of 'reference man' (Sender 2016 PLOS Biol) the BMI of 20 kg·m-2 as BMI°. BME cutoff points for overweight and obese are then obtained for BMI cutoffs of 25 and 30 kg·m-2 at heights of 1.79 and 1.85 m, respectively.
- » Further details: BME cutoff points).
MitoPedia: BME
References
- WHO Multicentre Growth Reference Study Group (2006) WHO child growth standards based on length/height, weight and age. Acta Pædiatrica Suppl 450:76-85. - »Bioblast link«
- WHO Multicentre Growth Reference Study Group (2006) WHO child growth standards: length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: Methods and development. Geneva: World Health Organization:312 pp. - »Bioblast link«
- Zucker TF (1962) Regression of standing and sitting weights on body weight: man. In: Altman PL, Dittmer DS, eds: Growth including reproduction and morphological development. Committee on Biological Handbooks, Fed Amer Soc Exp Biol:336-7. – Anthropometry, H and M°, of the healthy reference population, HRP; based on [3.1-3.5]. - »Bioblast link«
- Bayley N, Davis FC (1935) Growth changes in bodily size and proportions during the first three years. Biometrika 27:26-87.
- Gray H, Ayres JG (1931) Growth in private school children. Behavior Res Fund Monog, Univ Chicago Press, Chicago:282 pp. – With averages and variabilities based on 3110 measurings on boys and 1473 on girls from the ages of one to nineteen years.
- Meredith HV (1935) Univ Iowa studies in child welfare 11(3).
- Peatman JG, Higgons RA (1938) Growth norms from birth to the age of five years: a study of children reared with optimal pediatric and home care. Am J Diseases Children 55:1233-1247.
- Simmons KW (1944) Monographs Soc Research in Child Develop 9(1).
- Body mass excess
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