NICE waist-to-height ratio guidelines "to have a waist<0.5 of your height", are suitable for children but misleading for adolescents

Alan M Nevill; Caroline Brand; Ruoling Chen; Michael J Duncan; João F de C Silveira; Ana P Sehn; Cézane P Reuter

doi:10.1016/j.numecd.2025.104117

NICE waist-to-height ratio guidelines "to have a waist<0.5 of your height", are suitable for children but misleading for adolescents

Nutr Metab Cardiovasc Dis. 2025 May 8:104117. doi: 10.1016/j.numecd.2025.104117. Online ahead of print.

Authors

Alan M Nevill¹, Caroline Brand², Ruoling Chen¹, Michael J Duncan³, João F de C Silveira⁴, Ana P Sehn⁵, Cézane P Reuter⁵

Affiliations

¹ Faculty of Education, Health and Wellbeing, University of Wolverhampton, Walsall, UK.
² IRyS Group, Physical Education School, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
³ Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK.
⁴ Graduate Program in Health Promotion, University of Santa Cruz do Sul, Santa Cruz do Sul, RS, Brazil; Graduate Program in Human Movement Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: joaofranciscocs@hotmail.com.
⁵ Graduate Program in Health Promotion, University of Santa Cruz do Sul, Santa Cruz do Sul, RS, Brazil.

PMID: 40451675
DOI: 10.1016/j.numecd.2025.104117

Abstract

Background and aim: National Institutes of Clinical Excellence (NICE) "at-risk" guidelines (waist-to-height ratio (WC/HT) < 0.5) over penalizes shorter adults and fails to alert taller adults who may be at risk. The aim is to assess whether the "at-risk" guidelines recommended by NICE are appropriate for children, by assessing whether their WCs increase in proportion to their height, thus obeying the principle of "geometric similarity.".

Methods and results: Cross-sectional study including 11018 participants aged 7-17 years. We assessed whether the children's waist circumferences (WC) increased in proportion to their heights (HT) using the allometric power law, WC = a.HT^b. We also cross-tabulated children (7-13 yrs) and adolescents (14-17 yrs) by height categories (short<145 cm, average 145-175 cm, and tall>0.175 cm) to identify whether taller or shorter individuals were equally "at-risk" (WHTR>0.5). The power law identified children's height exponents was approximately 1 (geometrically similar), but older adolescents' height exponents were approximately 0.5. We also identified that the frequency of children "at-risk" was evenly spread across the 3 height groups. In contrast, shorter adolescents were more frequently "at-risk" compared with their taller peers.

Conclusions: NICE guidelines (WC/HT < 0.5) are suitable for, and fairly classify children (aged 7-12 years) "at-risk" irrespective of their height. In contrast, shorter adolescents are consistently more likely to be unfairly classified as "at-risk" compared with taller adolescents, i.e., NICE guidelines (WC/HT < 0.5) will unfairly classify many adolescents as being "at-risk", with shorter adolescents being consistently over-penalized compared with their taller peers who may well be lulled into a false sense of security.

Keywords: Geometric power law; Obesity; Pediatric; Risk; Weight status.

Copyright © 2025 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.