Cohort study of adolescents' memory performance & brain dose of microwave radiation from wireless EMF

Abstract

Cohort study of adolescents' memory performance & brain dose of microwave radiation from wireless EMF Foerster M., Thielens A., Joseph W., Eeftens M., Röösli M. (2018) A prospective cohort study of adolescents' memory performance and individual brain dose of microwave radiation from wireless communication. Environmental Health Perspectives. ehp.niehs.nih.gov Abstract BACKGROUND: The potential impact of microwave radiofrequency electromagnetic fields (RF-EMF) emitted by wireless communication devices on neurocognitive functions of adolescents is controversial. In a previous analysis, we found changes in figural memory scores associated with a higher cumulative RF-EMF brain dose in adolescents. OBJECTIVE: We aimed to follow-up our previous results using a new study population, dose estimation, and approach to controlling for confounding from media usage itself. METHODS: RF-EMF brain dose for each participant was modeled. Multivariable linear regression models were fitted on verbal and figural memory score changes over 1 y and on estimated cumulative brain dose and RF-EMF related and unrelated media usage (n=669-676). Because of the hemispheric lateralization of memory, we conducted a laterality analysis for phone call ear preference. To control for the confounding of media use behaviors, a stratified analysis for different media usage groups was also conducted. RESULTS: We found decreased figural memory scores in association with an interquartile range (IQR) increase in estimated cumulative RF-EMF brain dose scores: −0:22 (95% CI: −0:47, 0.03; IQR: 953 mJ=kg per day) in the whole sample, −0:39 (95% CI: −0:67, −0:10; IQR: 953 mJ=kg per day) in right-side users (n=532), and −0:26 (95% CI: −0:42, −0:10; IQR: 341 mJ=kg per day) when recorded network operator data were used for RF-EMF dose estimation (n=274). Media usage unrelated to RF-EMF did not show significant associations or consistent patterns, with the exception of consistent (nonsignificant) positive associations between data traffic duration and verbal memory. CONCLUSIONS: Our findings for a cohort of Swiss adolescents require confirmation in other populations but suggest a potential adverse effect of of RF-EMF brain dose on cognitive functions that involve brain regions mostly exposed during mobile phone use. doi.org Conclusion We found preliminary evidence suggesting that RF-EMF may affect brain functions such as figural memory in regions that are most exposed during mobile phone use. Our findings do not provide conclusive evidence of causal effects and should be interpreted with caution until confirmed in other populations. Associations with media use parameters with low RF-EMF exposures did not provide clear or consistent support of effects of media use unrelated to RF-EMF (with the possible exception of consistent positive associations between verbal memory and data traffic duration). It is not yet clear which brain processes could be potentially affected and what biophysical mechanism may play a role. Potential long-term risk can be minimized by avoiding high brain- exposure situations as occurs when using a mobile phone with maximum power close to the ear because of, for example, bad network quality. Original study from 2015: Schoeni A., Roser K., Röösli M. (2015) Memory performance, wireless communication and exposure to radiofrequency electromagnetic fields: a prospective cohort study in adolescents. Environmental International. 85: 343-351. Highlights • This is a prospective cohort study with approx. one year of follow-up. • Self-reported and operator recorded mobile phone use data were collected. • The cumulative RF-EMF dose for the brain and for the whole body was calculated. • Associations were stronger for RF-EMF dose than for use of wireless devices. • RF-EMF exposure might impair memory performance in adolescents. Abstract BACKGROUND: The aim of this study is to investigate whether memory performance in adolescents is affected by radiofrequency electromagnetic fields (RF-EMF) from wireless device use or by the wireless device use itself due to non-radiation related factors in that context. METHODS: We conducted a prospective cohort study with 439 adolescents. Verbal and figural memory tasks at baseline and after one year were completed using a standardized, computerized cognitive test battery. Use of wireless devices was inquired by questionnaire and operator recorded mobile phone use data was obtained for a subgroup of 234 adolescents. RF-EMF dose measures considering various factors affecting RF-EMF exposure were computed for the brain and the whole body. Data were analysed using a longitudinal approach, to investigate whether cumulative exposure over one year was related to changes in memory performance. All analyses were adjusted for relevant confounders. RESULTS: The kappa coefficients between cumulative mobile phone call duration and RF-EMF brain and whole body dose were 0.62 and 0.67, respectively for the whole sample and 0.48 and 0.28, respectively for the sample with operator data. In linear exposure-response models an interquartile increase in cumulative operator recorded mobile phone call duration was associated with a decrease in figural memory performance score by - 0.15 (95% CI: -0.33, 0.03) units. For cumulative RF-EMF brain and whole body dose corresponding decreases in figural memory scores were -0.26 (95% CI: -0.42, -0.10) and -0.40 (95% CI: -0.79, -0.01), respectively. No exposure-response associations were observed for sending text messages and duration of gaming, which produces tiny RF-EMF emissions. CONCLUSIONS: A change in memory performance over one year was negatively associated with cumulative duration of wireless phone use and more strongly with RF-EMF dose. This may indicate that RF-EMF exposure affects memory performance. sciencedirect.com

AI evidence extraction

Main findings

Modeled cumulative RF-EMF brain dose was associated with decreased figural memory score change over 1 year (e.g., −0.22 per IQR increase in whole sample; stronger decrease in right-side users and when operator data were used for dose estimation). Media usage unrelated to RF-EMF showed no significant associations or consistent patterns, except consistent (nonsignificant) positive associations between data traffic duration and verbal memory.

Outcomes measured

• Figural memory score change
• Verbal memory score change
• Laterality analysis by phone call ear preference

Limitations

• Authors state findings require confirmation in other populations
• Authors state results are preliminary and do not provide conclusive evidence of causal effects
• Potential confounding from media usage behaviors addressed via stratified analyses (residual confounding still possible)
• RF-EMF brain dose was modeled/estimated (not directly measured)

Suggested hubs

• mobile-phones (0.9)
  Study evaluates RF-EMF brain dose largely from mobile phone use and relates it to memory outcomes.

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    "population": "Adolescents (Swiss adolescents mentioned)",
    "sample_size": 676,
    "outcomes": [
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