Prospective BMI changes in preschool children are associated with parental characteristics and body weight perceptions: the ToyBox-study

Objective: To examine the effect of the intervention implemented in the ToyBox-study on changes observed in age- and sex-specific BMI percentile and investigate the role of perinatal factors, parental perceptions and characteristics on this change. Design: A multicomponent, kindergarten-based, family-involved intervention with a cluster-randomised design. A standardised protocol was used to measure children's body weight and height. Information was also collected from parents/caregivers via the use of validated questionnaires. Linear mixed effect models with random intercept for country, socio-economic status and school were used. Setting: Selected preschools within the provinces of Oost-Flanders and West-Flanders (Belgium), Varna (Bulgaria), Bavaria (Germany), Attica (Greece), Mazowieckie (Poland) and Zaragoza (Spain). Participants: A sample of 6268 preschoolers aged 3·5-5·5 years (51·9 % boys). Results: There was no intervention effect on the change in children's BMI percentile. However, parents' underestimation of their children's actual weight status, parental overweight and mothers' pre-pregnancy overweight/obesity were found to be significantly and independently associated with increases in children's BMI percentile in multivariate modelling. Conclusions: As part of a wide public health initiative or as part of a counseling intervention programme, it is important to assist parents/caregivers to correctly perceive their own and their children's weight status. Recognition of excessive weight by parents/caregivers can increase their readiness to change and as such facilitate higher adherence to favourable behavioural changes within the family.