A variety of study designs are used to measure the impact of an intervention on the weight and health of children with obesity. While the gold standard remains the randomized controlled trial, a common approach used in clinical practice because of convenience and ease is the ‘pre-post’ design. This includes following one group of participants and comparing changes over time, usually before and after a structured intervention.
A recent paper by Rijks et al in the Journal of Clinical Endocrinology and Metabolism is a higher profile example of this design; they showed that regardless of weight status (overweight, obesity, severe obesity), children across categories showed improvements in BMI. This is a novel finding since weight management success tends to decrease as obesity severity increases. So, is this something unique to their intervention, their local environment….or is it ‘regression to the mean’?
For two thoughtful perspectives on this issue, and what it means for evaluating interventions to prevent or manage obesity in children, check out papers published earlier this year by Skinner et al and Wake et al.