The Effects of the Jump-In Whole-School Intervention on the Weight Development of Children in Amsterdam, the Netherlands.

BACKGROUND: This study assessed the effects of the "Jump-in" whole-school intervention in Amsterdam, the Netherlands, on children's weight development by comparing children exposed to the intervention and controls from 3 other large Dutch cities. Jump-in is a comprehensive intervention that aims to stimulate healthy nutrition and physical activity in children at primary schools in Amsterdam. In addition, the relationship between the intervention's implementation degree and its effectiveness was studied. METHODS: Demographic and anthropometric data, collected by youth health care professionals via routine health checks at T0 (2014) and T1 (2019), were used to analyze possible intervention effects by comparing the weight development of children exposed to the Jump-in intervention versus unexposed controls. Implementation logs from health promotion professionals were used to determine intervention effects per implementation degree. Multilevel regression analyses were used for all analyses. RESULTS: In total, 4299 children were included mean age ± 5.5 years (T0), 10.6 years (T1), and ≈50% boys/girls at both times. Receiving the fully implemented intervention resulted in a decline in standardized body-mass index (zBMI) compared to the controls (-0.23, confidence interval [CI] -0.33, -0.13). It also led to higher odds to move into a healthier weight category over time (odds ratio [OR] 1.36, CI 1.06, 1.74), yet no statistically significant shift towards a healthy weight was found. CONCLUSIONS: Relative to the controls, children exposed to the intervention showed positive zBMI developments, with stronger effects when the implementation degree was higher. Despite positive results, creating more impact might require the further integration of school-based programs into whole-systems approaches that include other energy-balance behaviors.

Radiofrequency electromagnetic fields, screen time, and emotional and behavioural problems in 5-year-old children.

BACKGROUND: Little is known about the exposure of young children to radiofrequency electromagnetic fields (RF-EMF) and potentially associated health effects. We assessed the relationship of RF-EMF exposure from different sources and screen time exposure with emotional and behavioural problems in 5-year-old children. METHODS: Cross-sectional study including 3102 children aged 5 years from the Amsterdam Born Children and their Development (ABCD) study, in the Netherlands. Residential RF-EMF exposure from mobile phone base stations was estimated with a 3D geospatial radio wave propagation model. Residential presence of RF-EMF indoor sources (cordless phone base stations and Wireless Fidelity (WiFi)), children's mobile phone and cordless phone calls and screen time exposure (computer/video game and television watching) was reported by the mother. Teachers (n = 2617) and mothers (n = 3019) independently reported child emotional and behavioural problems using the Strengths and Difficulties Questionnaire. RESULTS: No associations were found between mobile phone and cordless phone calls and emotional and behavioural problems. Children exposed to higher RF-EMF levels from mobile phone base stations showed higher odds of maternal-reported emotional symptoms (OR 1.82, 95%CI 1.07 to 3.09). Children with cordless phone at home had lower odds of teacher-reported problematic prosocial behaviour (OR 0.68, 95%CI 0.48 to 0.97) and of maternal-reported peer relationship problems (OR 0.61, 95% CI 0.39 to 0.96). Children who watched television ≥1.5 h/day had higher odds of maternal-reported hyperactivity/inattention (OR 3.13, 95%CI 1.43 to 6.82). CONCLUSION: Mobile phone and cordless phone calls, which lead to peak RF-EMF exposures to the head, were not associated with any emotional and behavioural problems in 5-year-old children. Environmental RF-EMF exposure from mobile phone base stations and from indoor sources and television watching, which both contribute very little to RF-EMF exposure, were associated with specific emotional and behavioural problems but mainly when reported by the mothers. We cannot, however, discard residual confounding or reverse causality. Further longitudinal research in particular as children will increase the use of telecommunication devices with the age may help to better understand the exact contribution of the different RF-EMF exposure sources if any. Moreover, a thorough control for confounding is essential for a correct interpretation of the studies on screen time and emotional and behavioural problems.