The study design and methodology for the ARCHER study - adolescent rural cohort study of hormones, health, education, environments and relationships

The ARCHER study is a multidisciplinary, prospective, longitudinal cohort study in 400 adolescents to be conducted in two centres in regional Australia in the State of New South Wales. The overall aim is to determine how changes over time in puberty hormones independently affect the study endpoints which describe universal and risk behaviours, mental health and physical status in adolescents. Recruitment will commence in school grades 5, 6 and 7 (10–12？years of age). Data collection includes participant and parent questionnaires, anthropometry, blood and urine collection and geocoding. Data analysis will include testing the reliability and validity of the chosen measures of puberty for subsequent statistical modeling to assess the impact over time of tempo and onset of puberty (and their interaction) and mean-level repeated measures analyses to explore for significant upward and downward shifts on target outcomes as a function of main effects.The strengths of this study include enrollment starting in the earliest stages of puberty, the use of frequent urine samples in addition to annual blood samples to measure puberty hormones, and the simultaneous use of parental questionnaires.Adolescence is a time when interventions have the capacity to make changes in individual health trajectories [1-3]. The aim of this study is to understand the effects of longitudinal changes in puberty hormones, especially the onset and tempo of change, on adolescent health and well-being. The present paper presents the research protocol for the study, with an emphasis on the newer technologies which have made this type of study possible.The two prime hormones, or biological measures, of puberty are testosterone (in boys) and oestradiol (in girls) [4], [Figure？ 1. The dramatic hormone changes of puberty are a universal and unforgettable experience. Inevitably such a phenomenon prompts many assumptions about the effects of puberty hormones on wellbeing and health. However, the authentic, lon