Background: Puberty is critical life-stage where significant physical and behavioural changes occur and long-term health pathways are established. Overweight and obesity during adolescence is common and often persists, potentially affecting health trajectories into adulthood. Despite the dynamic changes occurring at this life-stage, there are limited longitudinal studies that examine weight and health trends across puberty. ARCHER (Adolescent Rural Cohort Hormones, Health, Education, Environments and Relationships) is an ongoing longitudinal study of rural-dwelling young adolescents exploring the influence of puberty hormone change on health and wellbeing over three years.
Methods: At baseline and annually, adolescents and one parent/guardian complete questionnaires that collect demographic, behavioural, social, psychological and mental health information. Adolescent anthropometry and body composition are also measured, with a fasting blood sample collected. Adolescents provide three-monthly urine samples for measurement of puberty hormones. Data: mean±SD.
Results: A total of 342 adolescents (55% male; 11% Indigenous) were recruited across western New South Wales, with 313 available for anthropometry at the year one time-point. Baseline age, BMI z-score and waist circumference were 11.8±1.0y (male: 11.8±1.0y; female: 11.7±1.0y), 0.55±1.21 (male: 0.51±1.20; female: 0.60±1.23) and 66.3±11.0cm (male: 65.9±11.5cm; female: 66.7±10.3cm) respectively. Over one year, mean change in BMI z-score was -0.02±0.36 (male: -0.03±0.36; female: 0.00±0.35) with overweight/obesity prevalence increasing from 32% (17% male) to 34% (18% male). Of those starting at healthy weight, 7% (3% male) became overweight at year one, and one boy showed a shift from overweight to obesity. Conversely, 16% (11% male) of adolescents who were overweight/obese at baseline had shifted into a lower z-score category. There was no significant change in BMI z-scores (p=0.45) or z-score categories (p=0.77) across the two time points.
Conclusion: Whilst overweight and obesity did not change significantly across the first year of the ARCHER study, it was a prevalent issue in this group. Ongoing collection and analysis of data from this cohort may uncover potential predictors of weight change and health trajectories across adolescence.