Tanner’s tempo of growth in adolescence: recent SITAR insights with the Harpenden Growth Study and ALSPAC

T. J. Cole

doi:10.1080/03014460.2020.1717615

Abstract

Background: James Tanner emphasised the “tempo” of growth, i.e. the adolescent spurt as summarised by its timing (age at peak velocity or APV) and intensity (peak velocity, PV).Aim: The paper applies the SITAR growth curve model to pubertal growth data with the aim of clarifying the growth pattern across multiple measurements and the spectrum of APV and PV.Subjects and methods: Data for 7–20 years on ten anthropometric measurements in 619 children from the Harpenden Growth Study, and on height in 10410 children from the ALSPAC study, were analysed using SITAR (SuperImposition by Translation And Rotation). SITAR models pubertal growth as a mean curve with APV and PV fitted as subject-specific random effects, and a random measurement intercept.Results: Mean APV for Harpenden girls and boys averaged 12.0 and 13.9 years across the ten measurements. PV expressed as percent per year lay in the narrow range 4–8%. Splitting the ALSPAC subjects into 9 by 5 APV and PV groups and fitting separate SITAR models to each group confirmed SITAR’s good fit while highlighting the spectrum of growth patterns.Conclusion: SITAR works well to summarise pubertal growth. The disappointment is that Tanner did not live to see it in action.

Highlights

The human adolescent growth spurt is a remarkable phenomenon seen in few other primate species
The aim of this paper is to celebrate the legacy of Tanner – and Whitehouse – by using SuperImposition by Translation and Rotation (SITAR) to explore the adolescent growth spurt from two distinct perspectives: how it varies across ten distinct linear measurements from the age in years
Size indicates an up/down shift of the mean curve, reflecting how tall/short the individual is relative to the mean; timing reflects the individual at PV (APV), seen as a right/left shift in the curve, positive for a later peak than average and negative for earlier; and intensity reflects the rate of passage through puberty as measured by peak velocity (PV), positive for faster than average and negative for slower

Summary

Introduction

The human adolescent growth spurt is a remarkable phenomenon seen in few other primate species. Occurring towards the end of the growth period, after height velocity has been falling steadily since early infancy, the velocity suddenly increases to a peak of around 10 cm/year in boys and 8 cm/year in girls, a growth rate not seen since late infancy. Peak height velocity in individuals can occur as early as 10 years of age in girls or as late as 17 years in boys. James Tanner emphasised the “tempo” of growth, i.e. the adolescent spurt as summarised by its timing (age at peak velocity or APV) and intensity (peak velocity, PV). SITAR models pubertal growth as a mean curve with APV and PV fitted as subject-specific random effects, and a random measurement intercept. The disappointment is that Tanner did not live to see it in action

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Conclusion