Cookies help us deliver our services. By using our services, you agree to our use of cookies. More information

Healthy reference population

From Bioblast


high-resolution terminology - matching measurements at high-resolution


Healthy reference population

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 2020-01-20 linked to a preprint in preparation on BME and mitObesity.

From BMI to BME

Four allometric phases

HRP M-H.png
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 MĀ° at BME=0).
Figure 1: Four phases of the allometric relationship between body mass, MĀ°, 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, MĀ°, in the HRP for the same height. This difference is the excess body mass, ME = M-MĀ°, is normalized for MĀ°, we obtain the simple definition of the body mass excess, BME = ME/MĀ°. 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 BMIĀ° or precision BMI at BME=0. The normal BMI of 20 kgĀ·m-2 is obtained in the HRP at H=1.7 m and MĀ°=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).
HRP-BMI.png
Figure 2: Precision reference body mass index, BMIĀ°, with the BMIĀ°=20 kgĀ·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 kgĀ·m-2 (normal) and the precision BMIĀ°. For persons smaller than 1.7 m, the BMIĀ° is below 20 kgĀ·m-2, such that a BMI of 17.9 instead of 20 kgĀ·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 kgĀ·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 kgĀ·m-2 as BMIĀ°. BME cutoff points for overweight and obese are then obtained for BMI cutoffs of 25 and 30 kgĀ·m-2 at heights of 1.79 and 1.85 m, respectively.
Ā» Further details: BME cutoff points).
Figure 3: Growth curves and allometry of body mass and height in girls and boys from 5 to 19 years (WHO 2006). (a) and (b): Height and body mass as a function of age. The curves are very similar up to 13 years. (c) and (d) Body mass and precision body mass index, BMIĀ°, as a function of height. Three allometric phases are indicated by the shaded areas. The BMI does not yield an index that is independent of height.
Figure 3 is based on the WHO Child Growth Standards [1-3]. It illustrates the limitation of the BMI as an index of overweight and obesity. The precision body mass index, BMIĀ°, is claculated for the healthy reference population (HRP), in which neither underweight nor overweight prevails and which, therefore, should be characterized by a constant index. This is achieved by the body mass excess, BME [4], which relates the actual body mass, M, to the reference body mass, MĀ°, at a given height, BME=(M-MĀ°/MĀ°). The BME is constant at 0.0 for the HRP for both sexes independent of height. In contrast, the increase of the precision BMIĀ° from 15 to 21 kgĀ·m-2 from 1.0 to 1.8 m represents a confounding factor which explains the necessity of adjusting the BMI cutoff points. Instead of a focus on adjusted BMI cutoff points [3], research should focus on evaluation of the concept of BME and the HRP.



References

  1. WHO Multicentre Growth Reference Study Group (2006) WHO child growth standards based on length/height, weight and age. Acta PƦdiatrica Suppl 450:76-85.
  2. 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.
  3. de Onis M, Onyango AW, Borghi E, Siyam A, Nishida C, Siekmann J (2007) Development of a WHO growth reference for school-aged children and adolescents. Bull World Health Organization 85:660-7.
  4. 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. ā€“ Anthropometry, H and MĀ°, of the healthy reference population, HRP; based on [3.1-3.5]. - Ā»Bioblast linkĀ«
    1. Bayley N, Davis FC (1935) Growth changes in bodily size and proportions during the first three years. Biometrika 27:26-87.
    2. Gray H, Ayres JG (1931) Growth in private school children. Behavior Res Fund Monog, Univ Chicago Press, Chicago:282 pp. ā€“ With averages and variabilities based on 3110 measurings on boys and 1473 on girls from the ages of one to nineteen years.
    3. Meredith HV (1935) Univ Iowa studies in child welfare 11(3).
    4. 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.
    5. Simmons KW (1944) Monographs Soc Research in Child Develop 9(1).
  5. Body mass excess


MitoPedia: BME and mitObesity

Ā» Body mass excess and mitObesity | BME and mitObesity news | Summary |

TermAbbreviationDescription
BME cutoff pointsBME cutoffObesity is defined as a disease associated with an excess of body fat with respect to a healthy reference condition. Cutoff points for body mass excess, BME cutoff points, define the critical values for underweight (-0.1 and -0.2), overweight (0.2), and various degrees of obesity (0.4, 0.6, 0.8, and above). BME cutoffs are calibrated by crossover-points of BME with established BMI cutoffs.
Body fat excessBFEIn the healthy reference population (HRP), there is zero body fat excess, BFE, and the fraction of excess body fat in the HRP is expressed - by definition - relative to the reference body mass, MĀ°, at any given height. Importantly, body fat excess, BFE, and body mass excess, BME, are linearly related, which is not the case for the body mass index, BMI.
Body massm [kg]; M [kgĀ·x-1]The body mass M is the mass (kilogram [kg]) of an individual (object) [x] and is expressed in units [kg/x]. Whereas the body weight changes as a function of gravitational force (you are weightless at zero gravity; your floating weight in water is different from your weight in air), your mass is independent of gravitational force, and it is the same in air and water.
Body mass excessBMEThe body mass excess, BME, is an index of obesity and as such BME is a lifestyle metric. The BME is a measure of the extent to which your actual body mass, M [kg/x], deviates from MĀ° [kg/x], which is the reference body mass [kg] per individual [x] without excess body fat in the healthy reference population, HRP. A balanced BME is BMEĀ° = 0.0 with a band width of -0.1 towards underweight and +0.2 towards overweight. The BME is linearly related to the body fat excess.
Body mass indexBMIThe body mass index, BMI, is the ratio of body mass to height squared (BMI=MĀ·H-2), recommended by the WHO as a general indicator of underweight (BMI<18.5 kgĀ·m-2), overweight (BMI>25 kgĀ·m-2) and obesity (BMI>30 kgĀ·m-2). Keys et al (1972; see 2014) emphasized that 'the prime criterion must be the relative independence of the index from height'. It is exactly the dependence of the BMI on height - from children to adults, women to men, Caucasians to Asians -, which requires adjustments of BMI-cutoff points. This deficiency is resolved by the body mass excess relative to the healthy reference population.
ComorbidityComorbidities are common in obesogenic lifestyle-induced early aging. These are preventable, non-communicable diseases with strong associations to obesity. In many studies, cause and effect in the sequence of onset of comorbidities remain elusive. Chronic degenerative diseases are commonly obesity-induced. The search for the link between obesity and the etiology of diverse preventable diseases lead to the hypothesis, that mitochondrial dysfunction is the common mechanism, summarized in the term 'mitObesity'.
Healthy reference populationHRPA healthy reference population, HRP, establishes the baseline for the relation between body mass and height in healthy people of zero underweight or overweight, providing a reference for evaluation of deviations towards underweight or overweight and obesity. The WHO Child Growth Standards (WHO-CGS) on height and body mass refer to healthy girls and boys from Brazil, Ghana, India, Norway, Oman and the USA. The Committee on Biological Handbooks compiled data on height and body mass of healthy males from infancy to old age (USA), published before emergence of the fast-food and soft-drink epidemic. Four allometric phases are distinguished with distinct allometric exponents. At heights above 1.26 m/x the allometric exponent is 2.9, equal in women and men, and significantly different from the exponent of 2.0 implicated in the body mass index, BMI [kg/m2].
Height of humansh [m]; H [mĀ·x-1]The height of humans, h, is given in SI units in meters [m]. Humans are countable objects, and the symbol and unit of the number of objects is N [x]. The average height of N objects is, H = h/N [m/x], where h is the heights of all N objects measured on top of each other. Therefore, the height per human has the unit [mĀ·x-1] (compare body mass [kgĀ·x-1]). Without further identifyer, H is considered as the standing height of a human, measured without shoes, hair ornaments and heavy outer garments.
Lengthl [m]Length l is an SI base quantity with SI base unit meter m. Quantities derived from length are area A [m2] and volume V [m3]. Length is an extensive quantity, increasing additively with the number of objects. The term 'height' h is used for length in cases of vertical position (see height of humans). Length of height per object, LUX [mĀ·x-1] is length per unit-entity UX, in contrast to lentgth of a system, which may contain one or many entities, such as the length of a pipeline assembled from a number NX of individual pipes. Length is a quantity linked to direct sensory, practical experience, as reflected in terms related to length: long/short (height: tall/small). Terms such as 'long/short distance' are then used by analogy in the context of the more abstract quantity time (long/short duration).
MitObesity drugsBioactive mitObesity compounds are drugs and nutraceuticals with more or less reproducible beneficial effects in the treatment of diverse preventable degenerative diseases implicated in comorbidities linked to obesity, characterized by common mechanisms of action targeting mitochondria.
ObesityObesity is a disease resulting from excessive accumulation of body fat. In common obesity (non-syndromic obesity) excessive body fat is due to an obesogenic lifestyle with lack of physical exercise ('couch') and caloric surplus of food consumption ('potato'), causing several comorbidities which are characterized as preventable non-communicable diseases. Persistent body fat excess associated with deficits of physical activity induces a weight-lifting effect on increasing muscle mass with decreasing mitochondrial capacity. Body fat excess, therefore, correlates with body mass excess up to a critical stage of obesogenic lifestyle-induced sarcopenia, when loss of muscle mass results in further deterioration of physical performance particularly at older age.
VO2maxVO2max; VO2max/MMaximum oxygen consumption, VO2max, is and index of cardiorespiratory fitness, measured by spiroergometry on human and animal organisms capable of controlled physical exercise performance on a treadmill or cycle ergometer. VO2max is the maximum respiration of an organism, expressed as the volume of O2 at STPD consumed per unit of time per individual object [mL.min-1.x-1]. If normalized per body mass of the individual object, M [kg.x-1], mass specific maximum oxygen consumption, VO2max/M, is expressed in units [mL.min-1.kg-1].


MitoPedia concepts: MiP concept 


Labels:






MitoPedia:BME