The effect of a multi-component school-based social network intervention on children's body mass index: a four-arm...

Methods: Four schools were randomly allocated to one of four conditions: a social network intervention using influence agents focusing on water consumption, physical activity, a combination of the two, or a passive control condition. Participants included a total of 201 6- to-11-year-old children (53.7% girls; M_age = 8.51, SD_age = 0.93). At baseline, 149 (76.0%) participants had a healthy weight, 29 (14.8%) had overweight and 18 (9.2%) had obesity.

Results: Linear mixed effect models indicated that a multi-component school-based social network intervention targeting both water consumption and physical activity was most effective in decreasing children's zBMI.

Conclusion: This study suggests that schools can contribute to the intervention of childhood obesity-even without involving the parents-by targeting both children's water consumption and physical activity through influential peers, but more research is needed to identify mechanisms of change.