This study evaluated the effect of an after-school group-based medium-intensity multicomponent behavioural intervention programme for children aged 8-12 years with overweight or obesity on body mass index standard deviation score (BMI SDS). In accordance with standardized protocols body weight and height were measured in 195 participants (88 boys, 107 girls) at baseline and at the end of the programme. A total of 166 children derived from a school-based monitoring system served as control group. Multivariate regression analyses examined the effect of the intervention and the independent factors associated with better outcomes in the intervention group.
Analysis of covariance showed a significant intervention effect on BMI SDS in favour of the intervention group (b-coefficient -0.13 ± 0.03; p< 0.01) compared with the control group. Change in BMI SDS between baseline and follow-up in the intervention group was associated with baseline age (b-coefficient 0.03 ± 0.02; p= 0.04) but was independent from gender, ethnicity, baseline BMI SDS, time between baseline and follow-up, school year and attendance rate.