long-term effect of an excess-weight-reduction intervention among iranian school children: a 13- month follow-up of a cluster randomized controlled trial

Background: childhood obesity and overweight have become major public health problems worldwide. to combat this problem, effective, sustainable, and consistent strategies are needed. in this study, the long-term effect of a school-based intervention for weight reduction was evaluated in primary school students in tehran, iran. methods: this was a cluster randomized controlled trial (rct) conducted in 12 primary schools in a low- to middle-class district in tehran, iran. the participants were 334 overweight or obese primary school students (girls =164) based on world health organization standards, equally distributed in the intervention (n=167) and comparison (n=167) groups. it was a multi-component intervention and included nutrition education and increased physical activity (pa), a lifestyle modification program for parents, and changing the food items sold in canteens of the schools. body mass index z-score [bmi-z] was determined as the primary outcome and measured at baseline, three months after baseline, at post-test (after 18 weeks), and follow-up (13-month). in total, 205 students (59.5%) completed the follow-up. analyses were carried out based on the intention-to-treat principle using linear mixed models. results: after 13 months, the bmi z-score decreased in both intervention and comparison groups. however, the change was more significantly observed in the intervention group (adjusted change: 0.098, 95% ci: (0.03-0.16) compared with comparison group (p=0.003(. the intervention had a more significant effect on bmi z-score among girls (adjusted change: 0.36, 95% ci: (0.27-0.45) compared with the comparison group (p<0.001)( than among boys (adjusted change: -0.14, 95% ci: (-0.23- -0.05) compared with the comparison group (p=0.002). conclusion: the intervention was an effective way to reduce bmi in the girls and the effect lasted for a relatively long time.