Clinical research in adolescents: challenges and opportunities using obesity as a model.

Adolescent medicine is relatively young, compared to paediatric or adult medicine. Descriptive and observational studies have dominated the adolescent literature, including those studies published in the International Journal of Obesity. In addition, many studies have combined child and adolescent age groups, making it difficult to determine adolescent-specific outcomes. It is important that high quality intervention studies in adolescents occur. Adolescence is a time of extraordinary plasticity. Habits, attitudes and physical morbidity that develop during adolescence set up trajectories that have a profound influence on health and wellbeing for the long term. Overweight and obesity are an excellent example of the need for high quality intervention studies and yet in the last two decades there have been very few randomized, controlled trials of overweight and obesity management in adolescents. There are a number of complexities in adolescent research that create additional challenges to those that accompany any clinical research. These include recruitment and retention, issues around consent and confidentiality and the central role that parents play in supporting the research protocol. Pubertal stage is a potential confounder and needs to be accurately measured. This is certainly true for studies in overweight and obesity where excess adiposity influences pubertal and other hormones. The opportunities to undertake quality research in adolescents are likely to be enhanced by the use of novel approaches which acknowledge the unique features of adolescents and their world.