Thursday, February 11, 2016

Exposure to radiofrequency radiation may cause cognitive & behavioral effects in 10-year-old boys

Does exposure to environmental radiofrequency electromagnetic fields cause cognitive and behavioral effects in 10-year-old boys?

Calvente, I., Pérez-Lobato, R., Núñez, M.-I., Ramos, R., Guxens, M., Villalba, J., Olea, N. and Fernández, M. F. (2016), Does exposure to environmental radiofrequency electromagnetic fields cause cognitive and behavioral effects in 10-year-old boys?. Bioelectromagnetics, 37: 25–36. doi: 10.1002/bem.21951.

The relationship between exposure to electromagnetic fields from non-ionizing radiation and adverse human health effects remains controversial. We aimed to explore the association of environmental radiofrequency-electromagnetic fields (RF-EMFs) exposure with neurobehavioral function of children.

A subsample of 123 boys belonging to the Environment and Childhood cohort from Granada (Spain), recruited at birth from 2000 through 2002, were evaluated at the age of 9–11 years. Spot electric field measurements within the 100 kHz to 6 GHz frequency range, expressed as both root mean-square (S
RMS) and maximum power density (SMAX) magnitudes, were performed in the immediate surrounds of children's dwellings. Neurocognitive and behavioral functions were assessed with a comprehensive battery of tests. Multivariate linear and logistic regression models were used, adjusting for potential confounders.

All measurements were lower than reference guideline limits, with median S
RMS and SMAX values of 285.94 and 2759.68 μW/m2, respectively. Most of the cognitive and behavioral parameters did not show any effect, but children living in higher RF exposure areas (above median SRMS levels) had lower scores for verbal expression/ comprehension and higher scores for internalizing and total problems, and obsessive-compulsive and post-traumatic stress disorders, in comparison to those living in areas with lower exposure. These associations were stronger when SMAX values were considered. 

Although some of our results may suggest that low-level environmental RF-EMF exposure has a negative impact on cognitive and/or behavior development in children; given limitations in the study design and that the majority of neurobehavioral functioning tasks were not affected, definitive conclusions cannot be drawn.
Excerpts... There is particular concern about the potential effects of exposure to RF-EMF on children [Bakker et al., 2011], who may be more vulnerable than adults, although this question remains under debate [van Rongen et al., 2009]. It has been proposed that children could be more sensitive to RF-EMF because they are still in a physiological and psychological development period [Kheifets et al., 2005; Schüz, 2005]. Studies investigating potential causal relationships between RF-EMF exposure and adverse health outcomes have mostly focused on childhood cancers [Calvente et al., 2010; Teepen and van Dijck, 2012] and brain neoplasms [Li et al., 2012]. There has been little exploration of its effects on behavioral problems [Divan et al., 2008, 2012; Thomas et al., 2010a,b; Guxens et al., 2013], or psychosocial risk [Sansone and Sansone, 2013]. In fact, research on the potential effects of exposure to RF-EMFs on neurobehavioral function in children is scant and has largely focused on the association between cell phone use and behavioral problems [Divan et al., 2008, 2012; Thomas et al., 2010b; Feychting, 2011; Guxens et al., 2013]. Findings from the Danish National Birth Cohort showed a positive and dose-dependent relationship between cell phone use by mothers during pregnancy and behavioral problems in their offspring [Divan et al., 2008, 2012; Sudan et al.,2013]; however, this association was not supported by others [Guxens et al., 2013]. This discrepancy may be attributable to differences in outcome reporting (e.g., by parents and/or teachers) or exposure assessment (typically based on questionnaires) or to the presence of unmeasured confounding factors.

The setting of the INMA-Granada cohort is the health district of the San Cecilio University Hospital, including part of the city of Granada (236,000 inhabitants) and 50 towns and villages. Out of the 300 children/families enrolled in the study, the present work included the 123 (41%) families/dwellings for which outdoor RF-EMF measurements (surrounds of the dwellings) were finally carried out. Half of the dwellings (44.7%) were in an urban area (city of Granada), 45.5% in semi-urban areas (towns of >20,000 inhabitants in city residential belt), and 9.8% in rural areas (<20 inhabitants="" span="">

... A cell phone was possessed by 97.5% of the children but only 6.0% of the children used it ....

Median SRMS and SMAX values in the immediate surrounds of the childreńs dwellings were 285.94 μW/m2 and 2759.68 μW/m2, respectively, with a range of 5.51–11559.55 μW/m2 and 2.39–150001.06 μW/m2, respectively. Maximum SRMS and SMAX values were 11559.55 μW/m2and 150001.06 μW/m2, respectively. All measurements obtained were below the reference limit. The mean distance from the dwellings to mobile phone base stations/aerials emitting GSM 900 and GSM 1800 was 660.87 ± 717.48 m, with a minimum distance of 35 m and maximum of 5000 m; 50% of the dwellings were within 500 m.

Environmental exposure to RF-EMF appeared to be associated with worse verbal expression/comprehension and with a few behavioral problems (internalizing and total problems, obsessive-compulsive and post-traumatic stress disorders) in the children in this study; however, the majority of neurobehavioral functioning tasks were not affected. Thus, children with higher exposure levels (SRMS ≥ 285.9 μW/m2) in the immediate surrounds of their dwellings had lower verbal expression/comprehension scores and higher behavioral and emotional problems, including anxious-depressed behaviors, OCD, and PTSD, in comparison to those in lower exposure areas levels (SRMS < 285.9 μW/m2). When exposure was measured as SMAX, similar results were observed for cognitive functions but worse results for internalizing and total behavior problems, finding lower IQ and school competence scores and higher ADHD and social and conduct problems (aggressive and rule-breaking behaviors) in children from higher (SMAX ≥ 2759.68 μW/m2) vs. lower exposure areas. The prevalence of total behavior problems was greater with higher exposure. Overall, 8.6% of the children were classified as borderline/clinical in the lower exposure group vs. 20.3% of those in the higher exposure group. Nevertheless, there are a number of issues that need to be critically considered.

...  all of measured exposure values in our study were several orders below current ICNIRP guideline limit [1998] recommended for the general population, in line with reports by Heinrich et al., [2010, 2011] and Thomas et al. [2010].

The present findings should also be interpreted with caution because statistical significance was only reached for one cognitive function and a few behavioral tasks, which may be due to chance or to the performance of multiple comparisons. Furthermore, as the design of the study was cross-sectional and the exposure and neurodevelopment were only assessed at one time point, it is not possible to determine whether the RF-EMF exposure had affected cognitive function or whether these findings represented pre-existing cognitive and/or behavioral development.

Some of the present findings may suggest that low-level environmental exposure to RF-EMFs has a negative impact on cognitive and/or behavioral development in children; however, given limitations in the study design and that the majority of neurobehavioral functioning tasks were not affected, definitive conclusions cannot be drawn. Further research is warranted to elucidate the potential risks of long-term exposure and to investigate the underlying mechanisms. A more standardized research approach is needed to reveal meaningful results on which risk assessment can be soundly based after evaluation of the relevance of any effects.

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Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

Electromagnetic Radiation Safety

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