Effectiveness of Sedentary Behaviour Interventions on Body Mass Index in Children

Abstract

The evidence supporting the association between sedentary behaviour (SB) and obesity in children is conflicting. Nevertheless, interventions aiming to prevent or treat overweight in children have been targeting SB as an attempt to include a wider range of factors associated with energy balance. PURPOSE: To summarize and compare the effect of interventions that target body mass index (BMI) in children. The secondary aim is to explore the impact of moderator variables (age, weight status, intervention type, duration, setting and study quality) on intervention effectiveness. METHODS: English-language publications up to March 2015 were located through electronic and manual searches. Interventions targeting sedentary activities in children (0 to 17 years old) with a control group and objective measure of weight and height were included. Mean change in BMI or BMI z-score from baseline to post-intervention between intervention and control group was calculated and meta-analysis was performed using a random effects model. RESULTS: Sixty-seven studies were included in the review. Sixteen studies were performed with pre-school children (0 to 5 years), 35 with children (5 to 11 years) and 16 with adolescents (12 to 17 years). Six studies targeted only SB, 10 studies targeted only SB and physical activity and 51 targeted SB and other behaviour(s). Nineteen studies reported a significant reduction in BMI or BMI z-score. Results from the meta-analysis revealed a small but significant effect on BMI and BMI z-score compared with controls (standardized mean difference (SMD) = -0.064, 95% confidence interval [CI] -0.091 to -0.038, I2= 75%). Interventions delivered in a non-educational setting (SMD= -0.161, CI: -0.218 to -0.105), to an overweight population (SMD = -0.159, CI:-0.229 to -0.089) and including SB and other behaviours (SMD= -0.074, CI: -0.108 to -0.041) appeared to improve effectiveness. CONCLUSIONS: The effect of SB interventions on BMI is small and unlikely to be clinically relevant. Nonetheless the impact of the intervention appeared to improve when SB interventions were delivered to an overweight population, implemented in a non-educational settings and in addition to other behaviours, showing that adopting a broader contextual approach might be more efficacious in targeting childhood obesity.