Open Access Study protocol

Study protocol: the Childhood to Adolescence Transition Study (CATS)

Lisa K Mundy12*, Julian G Simmons3, Nicholas B Allen3, Russell M Viner4, Jordana K Bayer15, Timothy Olds6, Jo Williams1278, Craig Olsson127, Helena Romaniuk189, Fiona Mensah189, Susan M Sawyer128, Louisa Degenhardt1011, Rosa Alati1213, Melissa Wake1148, Felice Jacka7 and George C Patton128

Author Affiliations

1 Murdoch Childrens Research Institute, Melbourne, Australia

2 Centre for Adolescent Health, The Royal Children’s Hospital, Melbourne, Australia

3 Melbourne School of Psychological Sciences, The University of Melbourne, Melbourne, Australia

4 UCL Institute of Child Health, University College London, London, UK

5 La Trobe University, Melbourne, Australia

6 Health and Use of Time (HUT) Group, University of South Australia, Adelaide, Australia

7 Deakin University, Melbourne, Australia

8 Department of Paediatrics, The University of Melbourne, Melbourne, Australia

9 Clinical Epidemiology and Biostatistics Unit, The Royal Children's Hospital, Melbourne, Australia

10 University of New South Wales, Sydney, Australia

11 Melbourne School of Population and Global Health, The University of Melbourne, Victoria, Australia

12 School of Population Health, University of Queensland, Brisbane, Australia

13 Centre for Youth Substance Abuse Research, University of Queensland, Brisbane, Australia

14 Centre for Community Child Health, The Royal Children’s Hospital, Melbourne, Australia

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BMC Pediatrics 2013, 13:160  doi:10.1186/1471-2431-13-160

Published: 8 October 2013



Puberty is a multifaceted developmental process that begins in late-childhood with a cascade of endocrine changes that ultimately lead to sexual maturation and reproductive capability. The transition through puberty is marked by an increased risk for the onset of a range of health problems, particularly those related to the control of behaviour and emotion. Early onset puberty is associated with a greater risk of cancers of the reproductive tract and cardiovascular disease. Previous studies have had methodological limitations and have tended to view puberty as a unitary process, with little distinction between adrenarche, gonadarche and linear growth. The Childhood to Adolescence Transition Study (CATS) aims to prospectively examine associations between the timing and stage of the different hormonally-mediated changes, as well as the onset and course of common health and behavioural problems that emerge in the transition from childhood to adolescence. The initial focus of CATS is on adrenarche, the first hormonal process in the pubertal cascade, which begins for most children at around 8 years of age.


CATS is a longitudinal population-based cohort study. All Grade 3 students (8–9 years of age) from a stratified cluster sample of schools in Melbourne, Australia were invited to take part. In total, 1239 students and a parent/guardian were recruited to participate in the study. Measures are repeated annually and comprise student, parent and teacher questionnaires, and student anthropometric measurements. A saliva sample was collected from students at baseline and will be repeated at later waves, with the primary purpose of measuring hormonal indices of adrenarche and gonadarche.


CATS is uniquely placed to capture biological and phenotypic indices of the pubertal process from its earliest manifestations, together with anthropometric measures and assessment of child health and development. The cohort will provide rich detail of the development, lifestyle, external circumstances and health of children during the transition from childhood through to adolescence. Baseline associations between the hormonal measures and measures of mental health and behaviour will initially be examined cross-sectionally, and then in later waves longitudinally. CATS will make a unique contribution to the understanding of adrenarche and puberty in children’s health and development.

Puberty; Hormones; Adrenarche; Gonadarche; Adolescent; Cohort studies; Public health; Protocol; Epidemiology