The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations

Background: Critical cut-off values of BMI-for-age z-scores (BAZ) are used to define “thinness”, “overweight” and “obesity”, but the validity of these cut-off values needs to be questioned in populations that are shorter or taller than the reference. We hypothesized that the prevalence of thinness,...

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Main Authors: Michael Hermanussen, Masiar Novine, Christiane Scheffler, Detlef Groth
Format: Article
Language:English
Published: Universitätsverlag Potsdam 2022-08-01
Series:Human Biology and Public Health
Subjects:
Online Access:https://www.human-biology-and-public-health.org/index.php/hbph/article/view/21
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author Michael Hermanussen
Masiar Novine
Christiane Scheffler
Detlef Groth
author_facet Michael Hermanussen
Masiar Novine
Christiane Scheffler
Detlef Groth
author_sort Michael Hermanussen
collection DOAJ
description Background: Critical cut-off values of BMI-for-age z-scores (BAZ) are used to define “thinness”, “overweight” and “obesity”, but the validity of these cut-off values needs to be questioned in populations that are shorter or taller than the reference. We hypothesized that the prevalence of thinness, overweight, and obesity depends on population height and performed a random simulation. Methods: We created virtual child populations aged 2-10 years with normally distributed height expressed as height-for-age z-scores (HAZ) and weight expressed as weight-for-age z-score (WAZ), based on WHO growth standards and references, with a correlation r=0.7 between height and weight. We adjusted weight-for-height and calculated BAZ. Results: BAZ depends on height and age. In short children (mean HAZ=-2 to HAZ=-3), the prevalence of thinness falls to less than 1% in the youngest and rises up to 10% (mean HAZ=-2) and up to 13% (mean HAZ=-3) at age 10 years. The prevalence of obesity rises to up to 7% in the shortest and youngest and falls close to zero at age 10. Short young children and tall older children are more prone to be misclassified as overweight. Conclusions: The prevalence of thinness, overweight and obesity depends on height and age. The coexistence of being short and being overweight – currently referred to as “double burden of malnutrition” – needs consideration as to what extent this condition is a health issue or reflects calculation artefacts. The arithmetic dilemma particularly affects young children in short populations. We suggest abstaining from defining “thinness”, “overweight”, or “obesity” by BMI z-scores. Different states of under- and malnutrition should rather be classified by direct or indirect measures of body fat.
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spelling doaj.art-3bc741531cfb4069be985952856a8e972024-04-02T07:03:55ZengUniversitätsverlag PotsdamHuman Biology and Public Health2748-99572022-08-01110.52905/hbph2022.1.21The arithmetic dilemma when defining thinness, overweight and obesity in stunted populationsMichael Hermanussen0https://orcid.org/0000-0003-4037-1597Masiar Novine1https://orcid.org/0000-0001-9687-8675Christiane Scheffler2https://orcid.org/0000-0003-1954-7578Detlef Groth3https://orcid.org/0000-0002-9441-3978Aschauhof 3, 24340 Eckernförde – Altenhof, GermanyUniversity of Potsdam, Bioinformatics, 14476 Potsdam-Golm, GermanyUniversity of Potsdam, Human Biology, 14469 Potsdam, GermanyUniversity of Potsdam, Bioinformatics, 14476 Potsdam-Golm, Germany Background: Critical cut-off values of BMI-for-age z-scores (BAZ) are used to define “thinness”, “overweight” and “obesity”, but the validity of these cut-off values needs to be questioned in populations that are shorter or taller than the reference. We hypothesized that the prevalence of thinness, overweight, and obesity depends on population height and performed a random simulation. Methods: We created virtual child populations aged 2-10 years with normally distributed height expressed as height-for-age z-scores (HAZ) and weight expressed as weight-for-age z-score (WAZ), based on WHO growth standards and references, with a correlation r=0.7 between height and weight. We adjusted weight-for-height and calculated BAZ. Results: BAZ depends on height and age. In short children (mean HAZ=-2 to HAZ=-3), the prevalence of thinness falls to less than 1% in the youngest and rises up to 10% (mean HAZ=-2) and up to 13% (mean HAZ=-3) at age 10 years. The prevalence of obesity rises to up to 7% in the shortest and youngest and falls close to zero at age 10. Short young children and tall older children are more prone to be misclassified as overweight. Conclusions: The prevalence of thinness, overweight and obesity depends on height and age. The coexistence of being short and being overweight – currently referred to as “double burden of malnutrition” – needs consideration as to what extent this condition is a health issue or reflects calculation artefacts. The arithmetic dilemma particularly affects young children in short populations. We suggest abstaining from defining “thinness”, “overweight”, or “obesity” by BMI z-scores. Different states of under- and malnutrition should rather be classified by direct or indirect measures of body fat. https://www.human-biology-and-public-health.org/index.php/hbph/article/view/21BMIstuntingprevalencethinnessobesitymisclassification
spellingShingle Michael Hermanussen
Masiar Novine
Christiane Scheffler
Detlef Groth
The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations
Human Biology and Public Health
BMI
stunting
prevalence
thinness
obesity
misclassification
title The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations
title_full The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations
title_fullStr The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations
title_full_unstemmed The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations
title_short The arithmetic dilemma when defining thinness, overweight and obesity in stunted populations
title_sort arithmetic dilemma when defining thinness overweight and obesity in stunted populations
topic BMI
stunting
prevalence
thinness
obesity
misclassification
url https://www.human-biology-and-public-health.org/index.php/hbph/article/view/21
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