Universal healthy school start intervention reduced the body mass index of young children with obesity.

AIM: To evaluate the effect of a universal, school-based family support programme on body mass index (BMI) of children aged 5-7 years, using pooled data from three trials. METHODS: The programme has three to four components and is delivered during the first school year. It aims to promote healthy dietary and physical activity behaviours, and secondarily prevent unhealthy weight gain. Three cluster-randomised controlled trials were conducted between 2010 and 2018 in low and mixed socioeconomic status areas in Sweden. Weight and height were measured. Multiple mixed linear regression analysis was performed on the pooled data. RESULTS: In total, 961 children were included (50% girls, mean age 6.3 years). The post-intervention effect on BMI z-score in all children was small, but in those with obesity at baseline, we observed a significant, clinically relevant, decrease in BMI z-score (-0.21). This was most pronounced in children with a non-Nordic born parent (-0.24). Five to six months after the intervention, decreases were no longer statistically significant. CONCLUSION: The intervention resulted in changes in BMI comparable to obesity treatment programmes focusing on behaviour change. However, the effect attenuated with time suggesting the programme should be sustained and evaluated for a longer time.