The Physical Behaviour Intensity Spectrum and Body Mass Index in School-Aged Youth: A Compositional Analysis of Pooled Individual Participant Data

Stuart J. Fairclough*, Liezel Hurter, Dorothea Dumuid, Ales Gába, Alex V. Rowlands, Borja del Pozo Cruz, Ashley Cox, Matteo Crotti, Lawrence Foweather, Lee E. F. Graves, Owen Jones, Deborah A. McCann, Robert J. Noonan, Michael B. Owen, James R. Rudd, Sarah L. Taylor, Richard Tyler, Lynne M. Boddy

*Corresponding author for this work

Research output: Contribution to journalArticle (journal)peer-review

Abstract

We examined the compositional associations between the intensity spectrum derived from incremental acceleration intensity bands and the body mass index (BMI) z-score in youth, and investigated the estimated differences in BMI z-score following time reallocations between intensity bands. School-aged youth from 63 schools wore wrist accelerometers, and data of 1453 participants (57.5% girls) were analysed. Nine acceleration intensity bands (range: 0−50 mg to ≥700 mg) were used to generate time-use compositions. Multivariate regression assessed the associations between intensity band compositions and BMI z-scores. Compositional isotemporal substitution estimated the differences in BMI z-score following time reallocations between intensity bands. The ≥700 mg intensity bandwas strongly and inversely associated with BMI z-score (p 0.001). The estimated differences in BMI z-score when 5 min were reallocated to and from the ≥700 mg band and reallocated equally among the remaining bands were −0.28 and 0.44, respectively (boys), and −0.39 and 1.06, respectively (girls). The time in the ≥700 mg intensity band was significantly associated with BMI z-score, irrespective of sex. When even modest durations of time in this band were reallocated, the asymmetrical estimated differences in BMI z-score were clinically meaningful. The findings highlight the utility of the full physical activity intensity spectrum over a priori-determined absolute intensity cut-point approaches.
Original languageEnglish
Pages (from-to)e8778
JournalInternational Journal of Environmental Research and Public Health
Volume19
Issue number14
Early online date19 Jul 2022
DOIs
Publication statusPublished - 19 Jul 2022

Keywords

  • accelerometer
  • CoDa
  • children
  • adolescents
  • physical activity
  • adiposity
  • intensity spectrum

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