ESPE Yearbook of Paediatric Endocrinology

Brief summary: Freedman et al. studied a cohort of n=343 preschool children (age 3-7 years) with a wide range of BMI to test the ability of 3 BMI metrics (BMI z-scores, percentage of the 50^th and 95^th percentile in CDC growth charts) to assess adiposity change (change in body fatness) over 4 years. They showed that changes in adiposity among young children are better captured by expressing changes in BMI as percentage of the 50th or 95th percentiles instead of as BMI z-score change.

It is essential for clinical management and for the interpretation of results of weight prevention programs, clinical trials, and monitoring of children, to use the best BMI metric to assess changes in body fatness. This paper clearly shows, for the age group of 3- to 7-years old children, that changes in %50th and %95th percentile are more strongly associated with changes in body fatness over 4 years than changes in BMI z-score. This work joins observations in older children and adolescents where the use of the BMI metrics %50th percentile and 95%th percentile better represented change in body fat mass than change in BMI z-score (1-3). Rather than focusing on change in BMI z-score, it would be preferable to use change in %50th or %95th percentile for clinical management and for monitoring of children over time.

References: 1. Løkling, H.L.; Roelants, M.; Kommedal, K.G.; Skjåkødegård, H.; Apalset, E.M.; Benestad, B.; Morken, M.H.; Hjelmesaeth, J.; Juliusson, P.B. Monitoring children and adolescents with severe obesity: body mass index (BMI), BMI z-score or percentage above the International Obesity Task Force overweight cut-off? Acta Paediatr 2019, 108, 2261-2266, doi:10.1111/apa.14898. 2. Kakinami, L.; Henderson, M.; Chiolero, A.; Cole, T.J.; Paradis, G. Identifying the best body mass index metric to assess adiposity change in children. Arch Dis Child 2014, 99, 1020-1024, doi:10.1136/archdischild-2013-305163. 3. Barlow, S.E.; Salahuddin, M.; Durand, C.; Pont, S.J.; Hoelscher, D.M.; Butte, N.F. Evaluation of BMI Metrics to Assess Change in Adiposity in Children with Overweight and Moderate and Severe Obesity. Obesity (Silver Spring) 2020, 28, 1512-1518, doi:10.1002/oby.22858.