Pediatric Obesity Prevention Initiatives:  More Questions Than Answers

The Girls health Enrichment Multi-site Studies (GEMS) was an obesity prevention initiative, with the aim of developing and testing interventions for African American girls.¹ Pilot studies were conducted at 4 sites, starting more than 10 years ago. Based on promising pilot data from the Memphis and Stanford sites,^2- 3 the National Heart, Lung, and Blood Institute funded 2 larger randomized controlled trials. The results of these trials, presented by Klesges et al⁴ and Robinson et al⁵ in this issue of the Archives, are undeniably discouraging. Changes in body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), the primary outcome, did not differ over 2 years between prevention and comparison groups in either study, despite outstanding investigative teams, extensive pilot work to develop culturally appropriate interventions that involved parents/caregivers or families, and substantial funding. To explore possible reasons for these null results and inform future research, several questions relating to the design of obesity prevention studies warrant consideration.