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BACKGROUND: Little is known about radiofrequency electromagnetic fields (RF) from mobile technology and resulting dose in young people. We describe modeled integrated RF dose in European children and adolescents combining own mobile device use and surrounding sources. METHODS: Using an integrated RF model, we estimated the daily RF dose in the brain (whole-brain, cerebellum, frontal lobe, midbrain, occipital lobe, parietal lobe, temporal lobes) and the whole-body in 8358 children (ages 8-12) and adolescents (ages 14-18) from the Netherlands, Spain, and Switzerland during 2012-2016. The integrated model estimated RF dose from near-field sources (digital enhanced communication technology (DECT) phone, mobile phone, tablet, and laptop) and far-field sources (mobile phone base stations via 3D-radiowave modeling or RF measurements). RESULTS: Adolescents were more frequent mobile phone users and experienced higher modeled RF doses in the whole-brain (median 330.4 mJ/kg/day) compared to children (median 81.8 mJ/kg/day). Children spent more time using tablets or laptops compared to adolescents, resulting in higher RF doses in the whole-body (median whole-body dose of 81.8 mJ/kg/day) compared to adolescents (41.9 mJ/kg/day). Among brain regions, temporal lobes received the highest RF dose (medians of 274.9 and 1786.5 mJ/kg/day in children and adolescents, respectively) followed by the frontal lobe. In most children and adolescents, calling on 2G networks was the main contributor to RF dose in the whole-brain (medians of 31.1 and 273.7 mJ/kg/day, respectively). CONCLUSION: This first large study of RF dose to the brain and body of children and adolescents shows that mobile phone calls on 2G networks are the main determinants of brain dose, especially in temporal and frontal lobes, whereas whole-body doses were mostly determined by tablet and laptop use. The modeling of RF doses provides valuable input to epidemiological research and to potential risk management regarding RF exposure in young people.

Objective: To investigate the association between estimated whole-brain radiofrequency electromagnetic fields (RF-EMF) dose, using an improved integrated RF-EMF exposure model, and cognitive function in preadolescents and adolescents. Methods: Cross-sectional analysis in preadolescents aged 9-11 years and adolescents aged 17-18 years from the Dutch Amsterdam Born Children and their Development Study (n = 1664 preadolescents) and the Spanish INfancia y Medio Ambiente Project (n = 1288 preadolescents and n = 261 adolescents), two population-based birth cohort studies. Overall whole-brain RF-EMF doses (mJ/kg/day) were estimated for several RF-EMF sources together including mobile and Digital Enhanced Cordless Telecommunications phone calls (named phone calls), other mobile phone uses than calling, tablet use, laptop use (named screen activities), and far-field sources. We also estimated whole-brain RF-EMF doses in these three groups separately (i.e. phone calls, screen activities, and far-field) that lead to different patterns of RF-EMF exposure. We assessed non-verbal intelligence in the Dutch and Spanish preadolescents, information processing speed, attentional function, and cognitive flexibility in the Spanish preadolescents, and working memory and semantic fluency in the Spanish preadolescents and adolescents using validated neurocognitive tests. Results: Estimated overall whole-brain RF-EMF dose was 90.1 mJ/kg/day (interquartile range (IQR) 42.7; 164.0) in the Dutch and Spanish preadolescents and 105.1 mJ/kg/day (IQR 51.0; 295.7) in the Spanish adolescents. Higher overall estimated whole-brain RF-EMF doses from all RF-EMF sources together and from phone calls were associated with lower non-verbal intelligence score in the Dutch and Spanish preadolescents (-0.10 points, 95% CI-0.19; -0.02 per 100 mJ/kg/day increase in each exposure). However, none of the whole-brain RF-EMF doses was related to any other cognitive function outcome in the Spanish preadolescents or adolescents. Conclusions: Our results suggest that higher brain exposure to RF-EMF is related to lower non-verbal intelligence but not to other cognitive function outcomes. Given the cross-sectional nature of the study, the small effect sizes, and the unknown biological mechanisms, we cannot discard that our resultsare due to chance finding or reverse causality. Longitudinal studies on RF-EMF brain exposure and cognitive function are needed.

Objective: To assess the association between estimated whole-brain and lobe-specific radiofrequency electromagnetic fields (RF-EMF) doses, using an improved integrated RF-EMF exposure model, and brain volumes in preadolescents at 9–12 years old. Methods: Cross-sectional analysis in preadolescents aged 9–12 years from the Generation R Study, a population-based birth cohort set up in Rotterdam, The Netherlands (n = 2592). An integrated exposure model was used to estimate whole-brain and lobe-specific RF-EMF doses (mJ/kg/day) from different RF-EMF sources including mobile and Digital Enhanced Cordless Telecommunications (DECT) phone calls, other mobile phone uses than calling, tablet use, laptop use, and far-field sources. Whole-brain and lobe-specific RF-EMF doses were estimated for all RF-EMF sources together (i.e. overall) and for three groups of RF-EMF sources that lead to a different pattern of RF-EMF exposure. Information on brain volumes was extracted from magnetic resonance imaging scans. Results: Estimated overall whole-brain RF-EMF dose was 84.3 mJ/kg/day. The highest overall lobe-specific dose was estimated in the temporal lobe (307.1 mJ/kg/day). Whole-brain and lobe-specific RF-EMF doses from all RF-EMF sources together, from mobile and DECT phone calls, and from far-field sources were not associated with global, cortical, or subcortical brain volumes. However, a higher whole-brain RF-EMF dose from mobile phone use for internet browsing, e-mailing, and text messaging, tablet use, and laptop use while wirelessly connected to the internet was associated with a smaller caudate volume. Conclusions: Our results suggest that estimated whole-brain and lobe-specific RF-EMF doses were not related to brain volumes in preadolescents at 9–12 years old. Screen activities with mobile communication devices while wirelessly connected to the internet lead to low RF-EMF dose to the brain and our observed association may thus rather reflect effects of social or individual factors related to these specific uses of mobile communication devices. However, we cannot discard residual confounding, chance finding, or reverse causality. Further studies on mobile communication devices and their potential negative associations with brain development are warranted, regardless whether associations are due to RF-EMF exposure or to other factors related to their use.

Introduction: Radiofrequency (RF) fields are widely used and, while it is still unknown whether children are more vulnerable to this type of exposure, it is essential to explore their level of exposure in order to conduct adequate epidemiological studies. Personal measurements provide individualized information, but they are costly in terms of time and resources, especially in large epidemiological studies. Other approaches, such as estimation of time-weighted averages (TWAs) based on spot measurements could simplify the work. Objectives: The aims of this study were to assess RF exposure in the Spanish INMA birth cohort by spot measurements and by personal measurements in the settings where children tend to spend most of their time, i.e., homes, schools and parks; to identify the settings and sources that contribute most to that exposure; and to explore if exposure assessment based on spot measurements is a valid proxy for personal exposure. Methods: When children were 8 years old, spot measurements were conducted in the principal settings of 104 participants: homes (104), schools and their playgrounds (26) and parks (79). At the same time, personal measurements were taken for a subsample of 50 children during 3 days. Exposure assessment based on personal and on spot measurements were compared both in terms of mean exposures and in exposure-dependent categories by means of Bland-Altman plots, Cohen's kappa and McNemar test. Results: Median exposure levels ranged from 29.73 (in children's bedrooms) to 200.10 μW/m2 (in school playgrounds) for spot measurements and were higher outdoors than indoors. Median personal exposure was 52.13 μW/m2 and median levels of assessments based on spot measurements ranged from 25.46 to 123.21 μW/m2. Based on spot measurements, the sources that contributed most to the exposure were FM radio, mobile phone downlink and Digital Video Broadcasting-Terrestrial, while indoor and personal sources contributed very little (altogether

Background: Exposure to radiofrequency electromagnetic fields (RF-EMF) from mobile communication technologies is changing rapidly. To characterize sources and associated variability, we studied the differences and correlations in exposure patterns between children aged 8 to 18 and their parents, over the course of the day, by age, by activity pattern, and for different metrics of exposure. Methods: Using portable RF-EMF measurement devices, we collected simultaneous real-time personal measurements of RF-EMF over 24 to 72 h in 294 parent-child pairs from Denmark, the Netherlands, Slovenia, Switzerland, and Spain. The devices measured the power flux density (mW/m(2)) in 16 different frequency bands every 4 s, and activity diary Apps kept by the participants were used to collect time-activity information in realtime. We analyzed their exposures by activity, for the different source constituents of exposure: downlink (radiation emitted from mobile phone base stations), uplink (transmission from phone to base station), broadcast, DECT (digital enhanced cordless telecommunications) and Wi-Fi. We looked at the correlations between parents and children overall, during day (06:00-22.00) and night (22:00-06:00) and while spending time at home. Results: The mean of time-weighted average personal exposures was 0.16 mW/m(2) for children and 0.15 mW/m(2) for parents, on average predominantly originating from downlink sources (47% for children and 45% for parents), followed by uplink (18% and 27% respectively) and broadcast (25% and 19%). On average, exposure for downlink and uplink were highest during the day, and for Wi-Fi and DECT during the evening. Exposure during activities where most of the time is spent (home, school and work) was relatively low whereas exposure during travel and outside activities was higher. Exposure to uplink increased with age among young people, while DECT decreased slightly. Exposure to downlink, broadcast, and Wi-Fi showed no obvious trend with age. We found that exposure to total RF-EMF is correlated among children and their parents (R-speannan = 0.45), especially while at home (0.62) and during the night (0.60). Correlations were higher for environmental sources such as downlink (0.57) and broadcast (0.62) than for usage-related exposures such as uplink (0.29). Conclusion: The generation gap between children and their parents is mostly evident in uplink exposure, due to more and longer uplink and cordless phone calls among parents, and their tendency to spend slightly more time in activities with higher environmental RF-EMF exposure, such as travel. Despite these differences in personal behavior, exposure to RF-EMF is moderately correlated between children and their parents, especially exposures resulting from environmental RF-EMF sources., GERoNiMO project: This work was supported by funding from the European Commission Seventh Framework Programme under grant agreement number FP7 603794.r HERMES project: This work is supported by the Swiss National Science Foundation (project number 138190). This research is also supported by the Swiss Research Foundation for Electricity and Mobile Communication (reference number 41).r ABCD, The Netherlands: This work is supported by the Netherlands Organisation for Health Research and Development (grant 2100.0076) and within the programme Electromagnetic Fields and Health Research (grants 85600004 and 85800001).r DNBC, Denmark: This work is supported by the Danish Epidemiology Science Centre; The Lundbeck Foundation; Egmont Foundation; March of Dimes Birth Defect Foundation; Augustinus Foundation; and the Medical Research Council.r ZuMe, Switzerland: This work is supported by the AWEL (Office for Waste, Water, Energy and Air) in Zurich.r INMA, Spain: This study was funded by grants from Instituto de Salud Carlos III (Red INMA G03/176; CB06/02/0041; PI041436; PI081151 incl. FEDER funds; PI12/01890 incl. FEDER funds; CP13/00054 incl. FEDER funds; MS13/00054), CIBERESP, Generalitat de Catalunya-CIRIT 1999SGR 00241, Generalitat de Catalunya-AGAUR (2009 SGR 501, 2014 SGR 822), Fundacio La marato de TV3 (090430), Spanish Ministry of Economy and Competitiveness (SAF2012-32991 incl. FEDER funds), Agence Nationale de Securite Sanitaire de l'Alimentation de l'Environnement et du Travail (1262C0010), European Commission (261357, 308333 and 603794). ISGlobal is a member of the CERCA Program, Generalitat de Catalunya.

With the recent evolution of mobile communication, there is a lack of understanding of increased radiofrequency (RF) exposure from these new technologies, especially among children. Little is known about the amount of RF exposure children experience day-to-day and its main sources. Furthermore, there is little understanding of RF dose during fetal life or RF dose to the brain during childhood. This thesis assessed environmental RF exposure and RF brain and body dose in children in several large, population-based cohort studies through personal exposure measurement studies and integrated exposure models. This thesis also evaluated whether maternal mobile phone use during pregnancy or RF dose to the brain in childhood was associated with neurodevelopmental outcomes, specifically, behavioral problems. In Europe, measured environmental RF in children and estimated dose to children’s brains was found to be far below recommended limits. Maternal mobile phone use during pregnancy was associated with hyperactivity/inattention problems in young children (ages 5-7) while RF dose to the brain during childhood was associated with behavioral problems, particularly in older children (ages 14-18). Uncontrolled confounding, reverse causality, and effects of mobile device use, apart from RF dose to the brain, could not be entirely excluded as possible explanations for these results. In the meantime, pregnant women could reduce RF exposure to the fetus by keeping mobile devices away from the belly, while children can reduce RF dose by limiting calls, limiting high resolution video streaming, or keeping mobile devices away from the body. Con la reciente evolución de la comunicación, existe una falta de comprensión del aumento de la exposición a la radiofrecuencia (RF) de estas nuevas tecnologías, especialmente entre los niños. Se sabe poco sobre la cantidad de exposición a RF que experimentan los niños día a día y sus principales fuentes. Además, hay poca comprensión de la cantidad de RF durante la vida fetal o la cantidad de RF en el cerebro durante la infancia. Esta tesis ha evaluado la exposición ambiental a RFs y la cantidad de RF en el cerebro y cuerpo en niños en varios estudios de cohorte de gran tamaño a través de estudios de medición de exposición personal y modelos de exposición integrados. Esta tesis también evaluó si el uso del teléfono móvil materno durante el embarazo o la cantidad de RF al cerebro en la infancia se asoció con problemas del desarrollo neurológico, específicamente, problemas de comportamiento. En Europa, la RF ambiental medida en niños y la cantidad estimada en el cerebro de los niños se encontraron muy por debajo de los límites recomendados. El uso del teléfono móvil materno durante el embarazo se asoció con problemas de hiperactividad/falta de atención en niños pequeños (entre 5 y 7 años) mientras que la cantidad de RF al cerebro durante la infancia se asoció con problemas de conducta, particularmente en niños mayores (14-18 años). Los factores de confusión no controlados, la causalidad inversa y los efectos del uso de dispositivos móviles, aparte de la cantidad de RF al cerebro, no podrían excluirse como posibles explicaciones para estos resultados. Además, las mujeres embarazadas podrían reducir la exposición a RF al feto manteniendo los dispositivos móviles alejados del estómago, mientras que los niños pueden reducir la cantidad de RF limitando las llamadas, limitando la transmisión de video de alta resolución o manteniendo los dispositivos móviles alejados del cuerpo.