A short note on the BMI and on secular changes in BMI
Keywords:body mass index, secular trend, weight-to-height ratio, malnutrition, obesity
Human size changes over time with worldwide secular trends in height, weight, and body mass index (BMI). There is general agreement to relate the state of nutrition to height and weight, and to ratios of weight-to-height. The BMI is a ratio. It is commonly used to classify underweight, overweight and obesity in adults. Yet, the BMI is inappropriate to provide any immediate information on body composition.
It is accepted that the BMI is “a simple index to classify underweight, overweight and obesity in adults”. It is stated that “policies, programmes and investments need to be “nutrition-sensitive”, which means they must have positive impacts on nutrition”. It is also stated that “a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions“. But these statements are neither warranted by arithmetic considerations, nor by historic evidence.
Measuring the BMI is an appropriate screening tool for detecting an unusual weight-to-height ratio, but the BMI is an inappropriate tool for estimating body composition, or suggesting medical and health policy decisions.
Bodzsaŕ, É.B./Susanne, C. (1998). Secular growth changes in Europe. Eötvös University Press.
Cossio Bolaños, M.A./Andruske, C.L./de Arruda, M., Sulla-Torres, J./Urra-Albornoz, C./Rivera-Portugal, M./Luarte-Rocha, C./Pacheco-Carrillo, J./Gómez-Campos, R. (2019). Muscle mass in children and adolescents: Proposed equations and reference values for assessment. Frontiers in Endocrinology 10, 583. https://doi.org/10.3389/fendo.2019.00583.
de Onis, M./Garza, C./Onyango, A.W./Borghi, E. (2007). Comparison of the WHO child growth standards and the CDC 2000 growth charts. Journal of Nutrition 137, 144–148. https://doi.org/10.1093/jn/137.1.144.
Fact sheets - Malnutrition [WWW Document] (n.d.). URL https://www.who.int/news-room/fact-sheets/detail/malnutrition (accessed 22.7.21).
Global Panel on Agriculture and Food Systems for Nutrition (2020). Future Food Systems: For people, our planet, and prosperity. London, UK. URL http://glopan.org/sites/default/files/ForesightReport.pdf (accessed 21.12.21).
Greil, H. (1988). Der Körperbau im Erwachsenenalter. Medical Faculty, Humboldt-University, Berlin.
López-Sánchez, G.F./Sgroi, M./D’Ottavio, S./Díaz-Suárez, A./González-Víllora, S./Veronese, N./Smith, L. (2019). Body composition in children and adolescents residing in Southern Europe: Prevalence of overweight and obesity according to different international references. Frontiers in Physiology 10, 130. https://doi.org/10.3389/fphys.2019.00130.
NCD Risk Factor Collaboration (NCD-RisC) (2021). Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight. eLife 10, e60060. https://doi.org/10.7554/eLife.60060.
NCD Risk Factor Collaboration (NCD-RisC) (2016). A century of trends in adult human height. eLife 5, e13410. https://doi.org/10.7554/eLife.13410.
OECD Glossary of Statistical Terms - BMI Definition [WWW Document] (n.d.). URL https://stats.oecd.org/glossary/detail.asp?ID=5458 (accessed 22.7.21).
Tanner, J.M./Hayashi, T./Preece, M.A./Cameron, N. (1982). Increase in length of leg relative to trunk in Japanese children and adults from 1957 to 1977: comparison with British and with Japanese Americans. Annals of Human Biology 9, 411–423. https://doi.org/10.1080/03014468200005951.
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Copyright (c) 2021 Michael Hermanussen; Rebekka Mumm
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