Sunday, December 19, 2021

Scientific American Created Confusion about 5G's Safety: Will They Clear It Up?

February 19, 2020 (Links to open access articles added on 12/19/2021)

In September 2019, Scientific American, the oldest, continuously published monthly magazine in the U.S., published an opinion piece on its website entitled, “5G Is Coming: How Worried Should We Be about the Health Risks? So far, at least, there’s little evidence of danger.” 

The piece was written by Kenneth Foster, an emeritus professor of bioengineering at the University of Pennsylvania. Foster is a member of a committee that sets exposure limits for wireless radiation and consults for industry and government. His article discussed the controversy about the rollout of 5G based upon widespread concerns about the adverse impact of this technology on our health. Foster argued that exposure to radio frequency radiation (RFR) from 5G will be similar to, or lower than, current levels because of the deployment of many “small cell” antennas. Hence, 5G exposure will comply with current RFR exposure limits that protect against “excessive heating of tissue.” 

Although Foster admitted that research on the effects of long-term exposure to 5G millimeter waves was lacking, he restated the FDA’s position that "[t]he available scientific evidence to date does not support adverse health effects in humans due to exposures at or under the current limits.” Thus, “the request to ‘stop the distribution of 5G products appears too drastic a measure. We first need to see how this new technology will be applied and how the scientific evidence will evolve.’”

In October, Scientific American published an opinion piece which I wrote entitled, “We Have No Reason to Believe 5G Is Safe:The technology is coming, but contrary to what some people say, there could be health risks,” that rebutted Foster’s article. My piece is reprinted on my Electromagnetic Radiation Safety website. 

In the eleven years that I have been writing about the effects of RFR exposure, I anticipated that my response to Foster would provoke an attack by industry-affiliated scientists so I began my piece as follows:

“The telecommunications industry and their experts have accused many scientists who have researched the effects of cell phone radiation of "fear mongering" over the advent of wireless technology's 5G. Since much of our research is publicly-funded, we believe it is our ethical responsibility to inform the public about what the peer-reviewed scientific literature tells us about the health risks from wireless radiation.”

I laid out the evidence that rebutted many points in the Foster piece and concluded:

“We should support the recommendations of the 250 scientists and medical doctors who signed the 5G Appeal that calls for an immediate moratorium on the deployment of 5G and demand that our government fund the research needed to adopt biologically-based exposure limits that protect our health and safety.”

About two weeks later, Scientific American published an opinion piece that attacked me and my article: “Don’t Fall Prey to Scaremongering about 5G: Activists cite low-quality studies in arguing radio-frequency radiation is dangerous, but the weight of evidence shows no risk.” This piece was written by David Robert Grimes, a science writer, cancer researcher, and physicist. 

Shortly after Grimes’ piece was published, the International EMF Alliance sent a 5-page letter to the editor of Scientific American that critiqued Grimes’ flawed interpretation of the science. Subsequently, Microwave News published a story entitled, “Open Season on 5G Critics: First NY Times, Now Scientific American,” reprinted by TruePublica, that criticized Grimes’ ad hominem attacks and explained why “it’s Grimes who gets the science all wrong.” The article raised the question “Why Did Scientific American Publish Grimes’s Hit Piece?"

Scientific American originally informed me that they would not publish a rebuttal to Grimes, but in January 2020 they invited me to submit a rebuttal. Two weeks after submitting my rebuttal, Scientific American sent me the following message:

“Thanks again for your recent submission, but we’ve decided against running it. You raise some valid points, but this is clearly a field where we’re a long way from definitive answers and the editors here have agreed that continuing this point-counterpoint argument in our opinion section is not the best way to serve our readers.

What we’ve decided to do instead is to commission an independent journalist to look at all of the evidence gathered so far and give readers an objective sense of what we know, what we don’t know, why uncertainty exists, and how scientists are trying to gather the evidence that governments and consumers need to make the most informed decisions possible.”

My unpublished rebuttal to Grimes, “5G, Public Health and Uncomfortable Truths” appears below.


5G, Public Health and Uncomfortable Truths

Joel M. Moskowitz, Ph.D.
School of Public Health
University of California, Berkeley
February 19, 2020

“So there really is no research ongoing. We’re kind of flying blind here, as far as health and safety is concerned,” proclaimed U.S. Senator Richard Blumenthal, chastising the Federal Communications Commission (FCC) and the Food and Drug Administration (FDA) in a Senate committee hearing on the future of 5G last year. This quote captures the reason why more than 270 scientists and medical doctors have signed the 5G Appeal, a petition calling for a moratorium on the deployment of 5G technology until we can establish safe exposure limits.  It is also one reason why I wrote about the status of the research and government and industry spin in “We Have No Reason to Believe 5G Is Safe.”

In an opinion piece that attacks my article, David Robert Grimes, a physicist, claims the research that finds radio-frequency radiation (RFR) is harmful is based on “low quality studies,” and that the weight of the evidence shows “no risk.” He repeats the mantra I have heard from other physicists in the ten years I have been studying the effects of cell phone radiation: “there is no known plausible biophysical mechanism of action for harm.” Grimes argues that my article “pivots on fringe views and fatally flawed conjecture, attempting to circumvent scientific consensus with scaremongering.”

Grimes’ arguments suffer the same biases he projects onto others (e.g., cherry-picking). His narrow perspective on the “mechanism of action for harm” seems shaped by a physics paradigm that can explain health risks from ionizing radiation (e.g., X-rays), but not from RFR (e.g., microwaves or cell phone radiation) which is non-ionizing. However, biologists have proposed various mechanisms that explain RFR effects. If not for his gaslighting and misrepresentations of published data, I might be charitably inclined to appreciate this debate. But Grimes aims to deny reality and discredit the preponderance of peer-reviewed science which finds low-intensity RFR can be harmful to our health.

The differences between the physicist’s and biologist’s perspectives could have been resolved decades ago had military and Telecom industry interests not interfered to ensure that RFR would be minimally regulated by policy makers. Microwave News has reported about these influences on scientific and policy developments since 1981. A recent Harvard monograph exposes how industry controls the FCC, the agency responsible for regulating RFR exposure from wireless technology in the U.S.

It is untrue, as Grimes argues, that RFR from cell phones cannot harm us because there is no mechanism. Numerous scientific studies provide evidence about mechanisms by which low-intensity RFR causes biological effects, including DNA damage in humans as well as animal models. For example, scientists who study RFR acknowledge that oxidative stress, an imbalance between free radicals and antioxidants, is a common mechanism by which RFR harms living cells. The uneven number of oxygen-containing electrons in free radicals allows them to react easily with other molecules. A review of 100 experimental studies on the oxidative effects of low-intensity RFR found that in 93 of these peer-reviewed studies “RFR induces oxidative effects in biological systems” leading to “cancer and non-cancer pathologies.” The review concluded, “the oxidative stress induced by RFR exposure should be recognized as one of the primary mechanisms of the biological activity of this kind of radiation.”

In an ideal world, I would agree with Grimes that “science is not conducted by petition or arguments to authority; it is decided solely on strength of evidence.” However, health authorities and policy makers have for decades relied upon industry-funded scientists who provide them with biased analyses that dismiss the peer-reviewed evidence unless it supports their sponsors. This is why independent scientists have sanctioned collective action.

More than 240 scientists from over 40 countries have signed the International EMF Scientist Appeal, a petition that raises concerns about the public health impacts of non-ionizing electromagnetic fields (EMF), especially from wireless technology. All have published peer-reviewed research on EMF and biology or health – totaling over 2,000 papers and letters in professional journals. Based upon solid evidence of harmful effects, these global experts urge public health leadership organizations, such as the World Health Organization (WHO), to establish more protective EMF guidelines and precautionary measures, and perform public education about health risks, particularly to children and developing fetuses.

Grimes cites the WHO’s current position that “no adverse health effects have been established as being caused by mobile phone use.” Setting aside the politics and limitations of that specific WHO declaration, note that the WHO’s own cancer research agency, the International Agency for Research on Cancer (IARC), classified RFR as “possibly carcinogenic to humans” in 2011. Last year, an IARC advisory group of 29 scientists examined the peer-reviewed research for RFR cancer risk published during the previous eight years and prioritized RFR for re-review. Hence, the IARC will likely upgrade the carcinogenic classification of RFR in the next five years.

Cited by Grimes is the one major cell phone radiation study conducted in the U.S. since the 1990’s. In 1999, the FDA recommended that the National Toxicology Program (NTP) research the carcinogenicity of cell phone radiation. The results of this $30 million study were published in 2018 after extensive peer review by EMF and toxicology experts. The NTP found “clear evidence” that cell phone radiation caused heart cancer and “some evidence” that it caused cancer in the brains and adrenal glands of male rats. The study also found significantly increased risk of DNA damage in rats and mice of both sexes exposed to cell phone radiation.

Whereas, most toxicologists consider the NTP methods the “gold standard,” Grimes erroneously implies that the NTP study’s “methodology and low power” would increase the likelihood that the study obtained spurious results. Statistically, a “low power” study has the opposite effect. Low statistical power means a study would be less likely to detect a real effect, not more likely to yield spurious effects. Grimes has thus repeated an industry-promoted canard about the study which reflects a complete misunderstanding of this basic statistical concept.

Characterizing the Interphone study among “large and robust trials, with careful controls and large sample groups” Grimes nevertheless misrepresents the study’s results. Careful reading of Interphone reveals a statistically significant increased risk of glioma and acoustic neuroma  among long-term heavy cell phone users. The researchers found that the excess glioma risk held up when the data were subjected to many different analyses (Appendix 1). Additional analyses that corrected for a bias in the study demonstrated a dose-response relationship between glioma risk and mobile phone use (see Appendix 2). 

Followup papers using the Interphone study data found that the excess tumors were primarily located on the side of the head where people held their phones, and in the part of the brain where cell phone radiation exposure was greatest, the temporal and frontal lobes.

Although three sources of case-control data  have found an association between ten years of heavy mobile phone use and glioma risk, glioma incidence may no longer be the best potential correlate of increased mobile phone use as Grimes implies. Long-term heavy mobile phone use is associated with various head and neck tumors in case-control studies including acoustic neuroma, meningioma, and tumors of the thyroid and parotid glands. In some countries glioma rates have increased in certain subgroups (e.g., older age groups, specific types of tumors or anatomic locations), if not overall. In many countries, including the U.S., thyroid tumor incidence has increased in recent years, and two case-control studies provide evidence that cell phone use may be responsible.

Bigger is not necessarily better. Besides the large Interphone study, Grimes cites the Danish cohort study as evidence that cell phone use is safe. However, this study has serious methodologic problems due to a wholly inadequate exposure assessment. Hence, the results from this study are not reliable.

The Telecom industry claims that their cellular technology is safe; yet, there are no safety studies on exposure to 4G or 5G cell phone radiation. Moreover, the weight of research evidence regarding exposure to 2G and 3G radiation finds harm including sperm damage in males, reproductive harm in females, neurological disorders, DNA damage and increased cancer risk.

There is room to disagree about the implications and quality of scientific studies, but it is disingenuous to disparage other scientists and employ industry talking points in the process, as Grimes does. The public has a right to know about the health risks of RFR. As Senator Blumenthal argued: “I believe that Americans deserve to know what the health effects are, not to pre-judge what scientific studies may show, and they also deserve a commitment to do the research on outstanding questions.”

Friday, December 17, 2021

Effects of Cell Phone Use on Adolescents

Trigger of a migraine headache among Thai adolescents smartphone users: 
a time series study

Wanna Chongchitpaisan, Phongtape Wiwatanadate, Surat Tanprawate, Assawin Narkpongphan, Nipapon Siripon. Trigger of a migraine headache among Thai adolescents smartphone users: a time series study. Environ Anal Health Toxicol. 2021 Mar; 36(1):e2021006-0. doi: 10.5620/eaht.2021006.


The study aims to investigate the effect of modern technology in the trigger of migraine headaches in high school students by using generalized estimating equation analysis. The prospective time series study was conducted in one hundred and forty-five smartphones using high school students in Chiang Mai Province who each completed a headache diary giving a total of 12,969 data entries. The smartphone output power was measured and recorded by a smartphone application. Smartphone use, sleep quality, anxiety, and depression also were assessed. Results revealed that the prevalence of repeated headache be 13.4% and migraine 16.9%. The migraine had the strongest association with handfree device use and internet use, followed by age and anxiety. Furthermore, the strongest effect of smartphone output power in triggering a migraine was found at ≤ 1.79×10-5 and 1.80-1.99×10-5 mW ranges. Meanwhile, Lag_6 of daily smartphone output power exposure produced the migraine effect in a reverse dose-response manner. The smartphone electromagnetic radiation was a primary migraine trigger. The study results led to the recommendation to avoid triggers by use of smartphone talking with hand-free devices to prevent a recurrent migraine.


SOP, which is smartphone electromagnetic radiation, has a non-linear correlation with migraine headaches which has been called a window effect response. The result has also found migraine response to a delayed effect of SOP in the form of reverse dose-response. The delayed effect response on repeated exposure can recover and re-balance itself after exposure to electromagnetic radiation. Additionally, smartphone electromagnetic radiation has effects that fit the criteria for triggers that induce migraines. Finally, younger student, internet use and talking without hand-free devices were risk factors of migraines. It is recommended that limited time for smartphone talking with hand-free device and older age starting using smartphone be suggested in order to prevent migraine attack.


On the Clear Evidence of the Risks to Children from Non-Ionizing Radio Frequency Radiation: The Case of Digital Technologies in the Home, Classroom and Society

"The level of proof required to justify action for health protection should be less than that required to constitute causality as a scientific principle” --
Professor Rainer Frentzel-Beyme MD


Children’s health and well-being is under significant threat from everyday digital technologies, as the past 15 years have seen the proliferation of microwave non-ionizing radio frequency radiation (RFR) devices and related communication systems in the home, school and society. The safety standards for such devices—smartphones, tablets etc.—and the systems that serve them, were based on the proven thermal effects of microwave radiation in adults, not children. As comprehensive research published between 1969-1976 by the U.S. Naval Medical Research Institute indicates, scientists have long been aware of equally harmful non-thermal effects—e.g. the risks of developing cancers, neurological, neurodegenerative, and other pathophysiological problems. However, physicists and engineers have operated on the theory that non-ionizing RFR could not directly damage human DNA and lead to cancer, as it was far less powerful than ionizing radiation (x-rays, nuclear etc.). That theory has been solidly and roundly refuted, as this paper illustrates. Nevertheless, industry-funded scientists continue to hold that non-thermal effects do not exist.However, thousands of independent research studies have demonstrated that low-intensity RFR elicits a range of pathophysiological conditions in experimental animals and humans. This is why parents, educators and governments should be alarmed, be better informed,and take immediate and appropriate action. This brief research review aims to inform by presenting the findings of scientific research, in a balanced, objective manner, on the risks to children. This information is based on proven scientific theories and clear empirical evidence. The paper concludes by offering practical advice on how the risks to children, and indeed adults, can be minimised.


Association between estimated whole-brain radiofrequency electromagnetic fields dose and cognitive function in preadolescents and adolescents

Alba Cabré-Riera, Luuk van Wel, Ilaria Liorni, Arno Thielens, Laura Ellen Birks, Livia Pierotti, Wout Joseph, Llúcia González-Safont, Jesús Ibarluzea, Amparo Ferrero, Anke Huss, Joe Wiart, Loreto Santa-Marina, Maties Torrent, Tanja Vrijkotte, Myles Capstick, Roel Vermeulen , Martine Vrijheid, Elisabeth Cardis, Martin Röösli, Mònica Guxens. Association between estimated whole-brain radiofrequency electromagnetic fields dose and cognitive function in preadolescents and adolescents. Int J Hyg Environ Health. 2020 Nov 19;231:113659. doi: 10.1016/j.ijheh.2020.113659.


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 results are due to chance finding or reverse causality. Longitudinal studies on RF-EMF brain exposure and cognitive function are needed.


Adolescence is a cognitive demanding stage of life, and one of the most rapid phases of human development. Therefore, it is important to identify factors that could compromise brain development at this stage and permanently impair cognitive abilities. Our results suggest that overall estimated whole-brain RF-EMF dose and specific dose from phone calls were related to lower non-verbal intelligence in preadolescents. However, our findings also indicate that whole-brain RF-EMF doses were not related to information processing speed, attentional function, visual attention, and cognitive flexibility in preadolescents or to working memory and semantic fluency in both preadolescents and adolescents. Given the cross-sectional nature of the study, the small effect sizes, and the unknown biological mechanisms, we cannot discard that our results might be due to chance finding or reverse causality. Our findings open the field to future longitudinal studies to further investigate the association between brain exposure to RF-EMF and cognitive function.


Estimated whole-brain and lobe-specific radiofrequency electromagnetic fields doses and brain volumes in preadolescents

Alba Cabré-Riera, Hanan El Marroun, Ryan Muetzel, Luuk van Wel, Ilaria Liorni, Arno Thielens, Laura Ellen Birks, Livia Pierotti, Anke Huss, Wout Joseph, Joe Wiart, Myles Capstick, Manon Hillegers, Roel Vermeulen, Elisabeth Cardis, Martine Vrijheid, Tonya White, Martin Röösli, Henning Tiemeier, Mònica Guxens. Estimated whole-brain and lobe-specific radiofrequency electromagnetic fields doses and brain volumes in preadolescents. Environment International. 142, September 2020, 105808.


• We estimated overall and source-specific RF-EMF doses to the brain.
• Estimated overall whole-brain RF-EMF dose was 84.3 mJ/kg/day.
• Overall whole-brain or lobe-specific RF-EMF doses were not related to brain volumes.
• Whole-brain RF-EMF dose from mobile communication devices for screen activities while wirelessly connected to the internet was associated with smaller caudate volume.
• We cannot discard residual confounding, chance finding, or reverse causality.


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.


Delayed sleep in six-year-old children was associated with excessive use of electronic devices at 12 years

Kato T, Yorifuii T, Yamakawa M, Inoue S. National data showed that delayed sleep in six-year-old children was associated with excessive use of electronic devices at 12 years. Acta Paediatr. 2018 Aug;107(8):1439-1448. doi: 10.1111/apa.14255.


AIM:  Cross-sectional studies have shown associations between adolescent sleep problems and the use of electronic devices, such as mobile phones, but longitudinal studies remain scarce. We explored any association between delayed bedtimes at six years old and the excessive use of electronic devices at 12 years of age. Texting was a prime focus.

METHODS:  We analysed 9607 adolescents who owned mobile phones in 2013 using the Japanese Longitudinal Survey of Newborns in the 21st Century, which started in 2001. The outcomes were daily excessive use of a mobile phone, television (TV) and video games.

RESULTS:  Delayed bedtime at the age of six years was associated with excessive texting at weekends. The adjusted odds ratios and 95% confidence intervals obtained from logistic regression analyses were 1.88 (1.14-3.10) for the 10-11 pm group and 1.98 (1.08-3.63) for the after 11 pm group, compared with the before 9 pm group. Later bedtimes were also associated with increased risks of excessive TV viewing and video game use.

CONCLUSION: Our study indicated that six-year-olds who regularly stayed up late at night used electronic devices more frequently, or for longer, at the age of 12. Parents need to be more aware of links between sleep issues and electronic devices.


Long-Term Symptoms of Mobile Phone Use on Mobile Phone Addiction 
and Depression Among Korean Adolescents

Park SY, Yang S, Shin CS, Jang H, Park SY. Long-Term Symptoms of Mobile Phone Use on Mobile Phone Addiction and Depression Among Korean Adolescents. Int J Environ Res Public Health. 2019 Sep 25;16(19). pii: E3584. doi: 10.3390/ijerph16193584.

This study aimed to compare the mean scores of mobile phone use, mobile phone addiction, and depressive symptoms at three-time points among Korean adolescents according to gender and to examine the differences in the long-term relationships among the three above-mentioned variables between Korean boys and girls in a four-year period. Data for 1794 adolescents (897 boys and 897 girls) were obtained from three waves of the second panel of the Korean Children and Youth Panel Survey. Multigroup structural equation modeling was used for data analyses. The study findings showed that at each of the three-time points, Korean girls tended to use their mobile phones more frequently and were at a higher risk of mobile phone addiction and depressive symptoms than Korean boys. Significant changes were observed in the longitudinal relationships among phone use, mobile phone addiction, and depressive symptoms in Korean adolescents across time periods, but no gender differences were found in the strengths of these relationships. These findings contribute to expanding the knowledge base of mobile phone addiction and depressive symptoms among Korean adolescents.


Short-term longitudinal relationships between smartphone use/dependency 
and psychological well-being among late adolescents

Lapierre MA, Zhao P, Custer BE. Short-term longitudinal relationships between smartphone use/dependency and psychological well-being among late adolescents. Journal of Adolescent Health (2019). DOI: 10.1016/j.jadohealth.2019.06.001


Purpose  The aim of the study was to determine the short-term longitudinal pathways between smartphone use, smartphone dependency, depressive symptoms, and loneliness among late adolescents.

Methods A two-wave longitudinal survey was used using adolescents between the ages of 17 and 20 years. The interval between wave 1 and wave 2 was between 2.5 and 3 months. Using convenience sampling, the total number of participants who completed both waves of data collection was 346. Validated measures assessed smartphone dependency, smartphone use, depressive symptoms, and loneliness. The longitudinal model was tested using path modeling techniques.

Results Among the 346 participants (33.6% male, mean [standard deviation] age at wave 1, 19.11 [.75] years, 56.9% response rate), longitudinal path models revealed that wave 1 smartphone dependency predicted loneliness (β = .08, standard error [SE] = .05, p = .043) and depressive symptoms (β = .11, SE = .05, p = .010) at wave 2, loneliness at wave 1 predicted depressive symptoms at wave 2 (β = .21, SE = .05, p < .001), and smartphone use at wave 1 predicted smartphone dependency at wave 2 (β = .08, SE = .05, p = .011).

Conclusions Considering the rates of smartphone ownership/use among late adolescents (95%), the association between smartphone use and smartphone dependency, and the deleterious effects of loneliness and depression within this population, health practitioners should communicate with patients and parents about the links between smartphone engagement and psychological well-being. 


Night-time screen-based media device use and adolescents' sleep 
and health-related quality of life

Mireku MO, Barker MM, Mutz J, Dumontheil I, Thomas MSC, Roosli M, Elliott P, Toledano MB. Night-time screen-based media device use and adolescents' sleep and health-related quality of life. Environ Int. 2019 Mar;124:66-78. doi: 10.1016/j.envint.2018.11.069


OBJECTIVE: The present study investigates the relationship between night-time screen-based media devices (SBMD) use, which refers to use within 1 h before sleep, in both lit and dark rooms, and sleep outcomes and health-related quality of life (HRQoL) among 11 to 12-year-olds.

METHODS: We analysed baseline data from a large cohort of 6616 adolescents from 39 schools in and around London, United Kingdom, participating in the Study of Cognition Adolescents and Mobile Phone (SCAMP). Adolescents self-reported their use of any SBMD (mobile phone, tablet, laptop, television etc.). Sleep variables were derived from self-reported weekday and/or weekend bedtime, sleep onset latency (SOL) and wake time. Sleep quality was assessed using four standardised dimensions from the Swiss Health Survey. HRQoL was estimated using the KIDSCREEN-10 questionnaire.

RESULTS: Over two-thirds (71.5%) of adolescents reported using at least one SBMD at night-time, and about a third (32.2%) reported using mobile phones at night-time in darkness. Night-time mobile phone and television use was associated with higher odds of insufficient sleep duration on weekdays (Odds Ratio, OR = 1.82, 95% Confidence Interval, CI [1.59, 2.07] and OR = 1.40, 95% CI [1.23, 1.60], respectively). Adolescents who used mobile phones in a room with light were more likely to have insufficient sleep (OR = 1.32, 95% CI [1.10, 1.60]) and later sleep midpoint (OR = 1.64, 95% CI [1.37, 1.95]) on weekends compared to non-users. The magnitude of these associations was even stronger for those who used mobile phones in darkness for insufficient sleep duration on weekdays (OR = 2.13, 95% CI [1.79, 2.54]) and for later sleep midpoint on weekdays (OR = 3.88, 95% CI [3.25, 4.62]) compared to non-users. Night-time use of mobile phones was associated with lower HRQoL and use in a dark room was associated with even lower KIDSCREEN-10 score (β = -1.18, 95% CI [-1.85, -0.52]) compared to no use.

CONCLUSIONS: We found consistent associations between night-time SBMD use and poor sleep outcomes and worse HRQoL in adolescents. The magnitude of these associations was stronger when SBMD use occurred in a dark room versus a lit room.


Prolonged mobile phone use is associated with depressive symptoms in Chinese adolescents

Liu J, Liu C, Wu T, Liu BP, Jia CX, Liu X. Prolonged mobile phone use is associated with depressive symptoms in Chinese adolescents. J Affec Disord. 12(259):128-134. Aug 2019. DOI: 10.1016/j.jad.2019.08.017.


Background: Prolonged screen time has negative impacts on health and well-being. This study examined the association between the duration of mobile phone use (DMPU) and depressive symptoms in a large sample of Chinese adolescents.

Methods: 11,831 adolescent students participated in the baseline Shandong Adolescent Behavior and Health Cohort (SABHC) survey in Shandong, China in 2015. A self-administered questionnaire was used to measure DMPU on weekdays and the weekend, sleep, mental health, and family environment. The Centre for Epidemiologic Studies Depression Scale (CES-D) and Youth Self-Report (YSR) depression scales were used to assess depressive symptoms.

Results: The mean age of participants was 15.0 (SD = 1.5) and 51% were male. The prevalence of depressive symptoms increased with prolonged DMPU. After adjusting for adolescent and family covariates, DMPU ≥ 2 h/day on weekdays (OR = 1.78, 95%CI = 1.48-2.15) and ≥ 5 h/day on the weekend (OR = 1.67, 95%CI = 1.41-1.98) was associated with increased risk of depressive symptoms as assessed by CES-D. The DMPU-depression association was found to be partially mediated by short sleep duration or insomnia. Similar associations were observed for depression as assessed by YSR.

Study Limitation: This is a cross-sectional survey. Mobile phone use and depressive symptoms were measured by self-report.

Conclusions: Prolonged mobile phone use of ≥ 2 hours on weekdays and ≥ 5 hours on the weekend is associated with an increased risk of depressive symptoms. The association appears to be partially mediated by sleep disturbances.


Problematic cell phone use, depression, anxiety & self-regulation: 
3-year longitudinal study from adolescence to emerging adulthood

Coyne SM, Stockdale L, Summers K. Problematic cell phone use, depression, anxiety, and self-regulation: Evidence from a three year longitudinal study from adolescence to emerging adulthood. Computers in Human Behavior. 96:78-84. July, 2019.


• Problematic cell phone use is stable between adolescence and emerging adulthood.
• Self-regulation and problematic cell phone use are not longitudinally related.
• Early problematic cell phone use is moderately associated with later depression.


For a small percentage of cell phone users, cell phone use becomes problematic or addictive, characterized by excessive time spent on the cell phone, interference with social relationships and responsibilities, and difficulty disengaging from cell phones. Researchers have argued that depression, anxiety, and self-regulation may be risk factors or outcomes of problematic cell phone use, but there are few longitudinal studies on problematic cell phone use, making it unclear if these behaviors are predictors or outcomes of problematic cell phone use. The current study examined these factors during late adolescence and the transition to emerging adulthood. Participants included 385 individuals between the ages of 17 and 19 who completed a series of questionnaires once a year over a three year period. Problematic cell phone use, anxiety, depression, and self-regulation were all moderately associated at the cross-sectional level. Early problematic cell phone use predicted later depression when these variables were examined longitudinally, as opposed to the converse. There were no longitudinal associations between problematic cell phone use and anxiety or self-regulation. In sum, problematic cell phone use was fairly stable across the transition from adolescence to emerging adulthood and was associated with depression in the future.


Social media use and adolescent mental health: Findings From the UK Millennium Cohort Study

Kelly Y, Zilanawala A, Booker C, Sacker A. (2019) Social media use and adolescent mental health: Findings from the UK Millennium Cohort Study. EClinicalMedicine. 10.1016/j.eclinm.2018.12.005. 2019. (In press)


BACKGROUND: Evidence suggests social media use is associated with mental health in young people but underlying processes are not well understood. This paper i) assesses whether social media use is associated with adolescents' depressive symptoms, and ii) investigates multiple potential explanatory pathways via online harassment, sleep, self-esteem and body image.

METHODS: We used population based data from the UK Millennium Cohort Study on 10,904 14 year olds. Multivariate regression and path models were used to examine associations between social media use and depressive symptoms.

FINDINGS: The magnitude of association between social media use and depressive symptoms was larger for girls than for boys. Compared with 1–3 h of daily use: 3 to < 5 h 26% increase in scores vs 21%; ≥ 5 h 50% vs 35% for girls and boys respectively. Greater social media use related to online harassment, poor sleep, low self-esteem and poor body image; in turn these related to higher depressive symptom scores. Multiple potential intervening pathways were apparent, for example: greater hours social media use related to body weight dissatisfaction (≥ 5 h 31% more likely to be dissatisfied), which in turn linked to depressive symptom scores directly (body dissatisfaction 15% higher depressive symptom scores) and indirectly via self-esteem.

INTERPRETATION: Our findings highlight the potential pitfalls of lengthy social media use for young people's mental health. Findings are highly relevant for the development of guidelines for the safe use of social media and calls on industry to more tightly regulate hours of social media use.

FUNDING: Economic and Social Research Council.


Among 14-year olds living in the UK, we found an association between social media use and depressive symptoms and that this was stronger for girls than for boys. The magnitude of these associations reduced when potential explanatory factors were taken into account, suggesting that experiences of online harassment, poorer sleep quantity and quality, self-esteem and body image largely explain observed associations. There was no evidence of differences for girls and boys in hypothesised pathways between social media use and depressive symptoms. Findings are based largely on cross sectional data and thus causality cannot be inferred.

Open access paper:


Telecommunication devices use, screen time and sleep in adolescents

Cabre-Riera A, Torrent M, Donaire-Gonzalez D, Vrijheid M, Cardis E, Guxens M. Telecommunication devices use, screen time and sleep in adolescents. 171:341-347. Apr 2019. DOI: 10.1016/j.envres.2018.10.036


• Telecommunication and other screen devices use was collected in adolescents
• Both subjective and objective sleep measures were assessed
• Tablet use and mobile phone dependency were associated with poorer sleep
• Frequency of cordless phone calls was associated with poorer sleep
• Public health recommendations on telecommunication devices use should be a priority


Purpose To investigate the association between telecommunication and other screen devices and subjective and objective sleep measures in adolescents at 17–18 years.

Methods Cross-sectional study on adolescents aged 17–18 years from a Spanish population-based birth cohort established in Menorca in 1997–1998. Information on devices use was collected using self-reported questionnaires. Mobile Phone Problematic Use Scale was used to assess mobile phone use dependency. Pittsburgh Sleep Quality Index was used to assess subjective sleep (n=226). ActiGraph wGT3X-BT for 7 nights was used to assess objective sleep (n=110).

Results One or more cordless phone calls/week was associated with a lower sleep quality [Prevalence Ratio PR 1.30 (95%CI 1.04; 1.62)]. Habitual and frequent problematic mobile phone use was associated with a lower sleep quality [PR 1.55 (95%CI 1.03; 2.33) and PR 1.67 (95%CI 1.09; 2.56), respectively]. Higher tablet use was associated with decreased sleep efficiency and increased minutes of wake time after sleep onset [β −1.15 (95%CI −1.99; −0.31) and β 7.00 (95%CI 2.40; 11.60) per increase of 10 minutes/day of use, respectively]. No associations were found between other devices and sleep measures.

Conclusions Tablet use, mobile phone use dependency, and frequency of cordless phone were related to an increase of subjective and objective sleep problems in adolescents. These results seem to indicate that sleep displacement, mental arousal, and exposure to blue light emission might play a more important role on sleep than a high RF-EMF exposure to the brain. However, more studies are needed assessing personal RF-EMF levels to draw conclusions.

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

Foerster M., Thielens A., Joseph W., Eeftens M., Röösli M. A prospective cohort study of adolescents' memory performance and individual brain dose of microwave radiation from wireless communication. Environmental Health Perspectives.126(7):077007. 2018. DOI: 10.1289/EHP2427.


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. 


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.

Note: The original study appears below (Schoeni et al., 2015).

Open access paper:


Decreases in sleep duration among U.S. adolescents 2009-2015 & association with new media screen time

Twenge JM, Krizan Z, Hisler G. Decreases in self-reported sleep duration among U.S. adolescents 2009-2015 and association with new media screen time. Sleep Med. 2017 Nov;39:47-53. doi: 10.1016/j.sleep.2017.08.013.


• More adolescents in 2015 (vs. 2009) slept less than 7 h a night on most nights.
• Electronic device and social media use also increased in 2009–2015.
• Electronic device and social media use increases the odds of short sleep duration. 
• Smartphones may be the cause of the increase in self-reported short sleep duration.


STUDY OBJECTIVES: Insufficient sleep among adolescents carries significant health risks, making it important to determine social factors that change sleep duration. We sought to determine whether the self-reported sleep duration of U.S. adolescents changed between 2009 and 2015 and examine whether new media screen time (relative to other factors) might be responsible for changes in sleep.

METHODS:We drew from yearly, nationally representative surveys of sleep duration and time use among adolescents conducted since 1991 (Monitoring the Future) and 2007 (Youth Risk Behavior Surveillance System of the Centers for Disease Control; total N = 369,595).

RESULTS: Compared to 2009, adolescents in 2015 were 16%-17% more likely to report sleeping less than 7 h a night on most nights, with an increase in short sleep duration after 2011-2013. New media screen time (electronic device use, social media, and reading news online) increased over this time period and was associated with increased odds of short sleep duration, with a clear exposure-response relationship for electronic devices after 2 or more hours of use per day. Other activities associated with short sleep duration, such as homework time, working for pay, and TV watching, were relatively stable or reduced over this time period, making it unlikely that these activities caused the sudden increase in short sleep duration.

CONCLUSIONS: Increased new media screen time may be involved in the recent increases (from 35% to 41% and from 37% to 43%) in short sleep among adolescents. Public health interventions should consider electronic device use as a target of intervention to improve adolescent health.


The effects of EMF on the endocrine system in children and adolescents

Sangün Ö, Dündar B, Çömlekçi S, Büyükgebiz A. The effects of electromagnetic field on the endocrine system in children and adolescents. Pediatr Endocrinol Rev. 2015 Dec;13(2):531-45.


Children are exposed to various kind of non-ionizing radiation in their daily life involuntarily. The potential sensitivity of developing organism to the effects of radiofrequency (RF) signals, the higher estimated specific absorption rate (SAR) values of children and greater lifetime cumulative risk raised the scientific interest for children's vulnerability to electromagnetic fields (EMFs). In modern societies, children are being exposed to EMFs in very early ages. There are many researches in scientific literature investigating the alterations of biological parameters in living organisms after EMFs. Although the international guidelines did not report definite, convincing data about the causality, there are unignorable amount of studies indicating the increased risk of cancer, hematologic effects and cognitive impairment. Although they are less in amount; growing number of studies reveal the impacts on metabolism and endocrine function. Reproductive system and growth look like the most challenging fields. However there are also some concerns on detrimental effects of EMFs on thyroid functions, adrenal hormones, glucose homeostasis and melatonin levels. It is not easy to conduct a study investigating the effects of EMFs on a fetus or child due to ethical issues. Hence, the studies are usually performed on virtual models or animals. Although the results are conflicting and cannot be totally matched with humans; there is growing evidence to distress us about the threats of EMF on children.


Does exposure to environmental RF EMF cause cognitive & 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.


November 19, 2015

Two recently published studies on adolescents report harmful effects of mobile phone use. A cross-sectional study found that adolescents who were awakened by a mobile phone at least once a month during the night were more likely to report tiredness, rapid exhaustibility, headache and physical ill-being. A prospective cohort study found that greater wireless radiation exposure predicted lower memory test performance.

Symptoms & cognitive functions in adolescents in relation to mobile phone use

Schoeni A, Roser K, Röösli M. Symptoms and cognitive functions in adolescents in relation to mobile phone use during night. PLoS One. 2015 Jul 29;10(7):e0133528. doi: 10.1371/journal.pone.0133528.


Many adolescents tend to leave their mobile phones turned on during night, accepting that they may be awakened by an incoming text message or call. Using self-reported and objective operator recorded mobile phone use data, we thus aimed to analyze how being awakened during night by mobile phone affects adolescents' perceived health and cognitive functions.

In this cross-sectional study, 439 adolescents completed questionnaires about their mobile phone use during night, health related quality of life and possible confounding factors. Standardized computerized cognitive tests were performed to assess memory and concentration capacity. Objective operator recorded mobile phone use data was further collected for 233 study participants. Data were analyzed by multivariable regression models adjusted for relevant confounders including amount of mobile phone use.

For adolescents reporting to be awakened by a mobile phone during night at least once a month the odds ratio for daytime tiredness and rapid exhaustibility were 1.86 (95% CI: 1.02-3.39) and 2.28 (95% CI: 0.97-5.34), respectively. Similar results were found when analyzing objective operator recorded mobile phone use data (tiredness: 1.63, 95% CI: 0.94-2.82 and rapid exhaustibility: 2.32, 95% CI: 1.01-5.36). The cognitive tests on memory and concentration capacity were not related to mobile phone use during night. Overall, being awakened during night by mobile phone was associated with an increase in health symptom reports such as tiredness, rapid exhaustibility, headache and physical ill-being, but not with memory and concentration capacity.

Prevention strategies should focus on helping adolescents set limits for their accessibility by mobile phone, especially during night.


Among Swiss adolescents, we have observed that nocturnal mobile phone use was associated with an increase in health symptom reports such as tiredness, rapid exhaustibility, headache and physical ill-being, but not with memory and concentration capacity. More studies to investigate these associations are necessary and education in sleep behaviour may be inevitable since the mobile phone is now the most familiar lifestyle factor for adolescents.

Public Health prevention strategies should focus on helping adolescents set limits for their accessibility by mobile phone, especially during night.

Open Access Paper:


Memory performance, wireless communication & RF EMF exposure: Prospective cohort study in adolescents

Schoeni A, Roser K, Röösli M. Memory performance, wireless communication and exposure to radiofrequency electromagnetic fields: A prospective cohort study in adolescents. Environ Int. 2015 Oct 13;85:343-351. doi: 10.1016/j.envint.2015.09.025.


• 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.


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.


... From a public health point of view potential effects of chronic exposure are more relevant, which needs to be investigated with epidemiological studies. So far there has only been one community-based epidemiological study investigating effects of mobile phone use on adolescents' memory. Abramson et al. (2009) showed in a cross-sectional analysis of 317 seventh grade students from Australia that mobile phone use was associated with faster and less accurate response on a number of tasks involving the memory. Since similar associations were found in relation to the number of SMS (short text messages), which produces negligible RF-EMF exposure, they speculated that these behaviours may have been learned through the frequent use of a mobile phone and may not be the consequence of mobile phone radiation. In a follow-up investigation one year later, in 236 of these students, an increase in mobile phone use was associated with a reduction in response time in one out of three tests involving the memory (Thomas et al., 2010). This study relied on self-reported mobile phone use only, which has been shown to be inaccurate. Adolescents tend to substantially overestimate their amount of mobile phone use (Aydin et al., 2011; Inyang et al., 2009).

Regular mobile phone use may affect adolescents in various ways. Thus, the main challenge for research consists in differentiating between RF-EMF radiation effects and other non-RF-EMF related effects from mobile phone use. For instance, frequent texting or gaming on a mobile phone may facilitate cognitive processes (Abramson et al., 2009). It was also observed, that calling and sending texts during night was associated with poor perceived health symptoms such as tiredness, rapid exhaustibility, headache and physical ill-being (Schoeni et al., 2015; Van den Bulck, 2007). Other studies showed that frequent mobile phone use was associated with anxiety (Jenaro et al., 2007), unhealthy lifestyle (Ezoe et al., 2009), depression (Yen et al., 2009) and psychological distress (Beranuy et al., 2009). Thus, to address RF-EMF effects of wireless communication devices, the development of a RF-EMF dose measure, which incorporates all exposure relevant factors, is inevitable.

Memory performance was assessed with a standardized, computerized cognitive test battery (IST, Intelligenz-Struktur-Test 2000R (Liepmann et al., 2006)). Verbal and figural memory was measured with the subtest of the IST. In the verbal memory task, word groups have to be memorized in one minute time. After 1 min the study participants give an account of the word groups that have been memorized. In total 10 points can be achieved by remembering the correct word groups. In the figural memory task, pairwise symbols have to be memorized in one minute time. After 1 min one part of the pairwise symbols is shown and the matching part has to be found. A total of 13 points can be achieved. For both the verbal and figural tests, 2 min is given to complete the test. Memory performance is considered as the right number of remembered word groups or symbols, respectively. For the statistical analyses of verbal and figural memory the continuous test score values
were used as outcome. Every test was conducted once at baseline and once at follow-up investigation.

In this study we considered objectively recorded data on mobile phone use collected from the Swiss mobile phone operators as well as self-reported data on wireless communication devices usage obtained from a written questionnaire referring to the 6 months period prior to each examination. In terms of RF-EMF related exposure measures we inquired about call duration with own or any other mobile phone (referred to as duration mobile phone calls), call duration with cordless (fixed line) phone and duration of data traffic on the mobile phone, e. g. for surfing and streaming. The duration of gaming on computers and TV and number of all kind of text messages (SMS, WhatsApp etc.) are not, or only marginally relevant for RF-EMF exposure and were thus inquired to be used as negative exposure control variables in the analyses.

Informed consent to obtain objectively recorded mobile phone use data from the mobile phone operators was given by 234 out of 439 study participants and their parents. This included duration of each call and on which network (GSM or UMTS) it started, number of SMS (text messages) sent per day and amount of volume of data traffic (MB/day). Data were obtained for up to 18 months, 6 months before baseline until follow-up investigation.

A particular strength of this study is the longitudinal design. To the best of our knowledge this is the first longitudinal study on memory performance in adolescents using not only mobile phone call duration as an exposure proxy, but calculating RF-EMF dose measures derived from objectively recorded operator data and propagation modelling. Compared to a cross-sectional design where changes over time cannot be assessed andwhere reverse causality is of concern, longitudinal studies allow for more robust conclusions.

.. Most relevant contributors for the brain dose are calls on the GSM network (on average 93.3% for the whole sample based on self-reported data and 58.7% for the sample with operator data using operator recorded information) followed by calls with the cordless phones (4.2% and 21.0%, respectively). For the whole body dose, calls on the GSM network (on average 66.9% for the whole sample and 19.5% for the sample with operator data), the use of computer/laptop/tablet connected to WLAN (12.0% and 29.1%, respectively) and data traffic on mobile phones over WLAN (8.1% and 22.3%, respectively) counted for the most part. Less important for the dose measures were exposure from radio and TV broadcast transmitters (brain dose: 0.1% and 0.4%, respectively; whole body dose: 0.3% and 0.9%, respectively) and mobile phone base stations (brain dose: 0.6% and 3.5%, respectively; whole body dose: 2.0% and 4.8%, respectively).

... media usage measures which are not, or only marginally associated with RF-EMF were not associated with figural memory performance (e.g. sending text messages, playing games, and duration/volume of data traffic on the mobile phone). On the other hand, mobile and cordless phone use,which involves RF-EMF exposure, tended to be negatively correlated, although not statistically significant, whereas the dose measures were significantly correlated in many models. The relative high correlation between dose measures and self-reported and objectively recorded mobile phone call duration respectively, limits the possibility to disentangle effects due to RF-EMF exposure or due to other factors associated with mobile phone use.

Since we found stronger associations between RF-EMF doses and figural memory but not verbal memory, one could speculate that this might be due to different brain areas involved in the verbal and figural memory tasks. The type of information being processed determines the brain activity during encoding and retrieval and as a consequence brain activity patterns during figural memory tasks differ fromthose observed during verbal memory tasks. During figural memory processes, encoding elicits bilateral prefrontal activity and retrieval increases the activity in bilateral or right-sided temporal regions and in bilateral prefrontal regions (Beason-Held et al., 2005; Roland and Gulyas, 1995; Wagner et al., 1998). During verbal encoding increases in prefrontal and temporal brain activity in the left hemisphere can be seen (Heun et al., 2000; Iidaka et al., 2000; Reber et al., 2002; Strandberg et al 2011) and during verbal retrieval the activity in bilateral or rightsided prefrontal regions, bilateral or left-sided temporal regions and the anterior cingulate are increased (Beason-Held et al., 2005; Buckner et al., 1998; Cabeza et al., 1997). Stronger overall effects observed for figural memory processes predominantly involving the right hemisphere compared to the verbal memory tasks mostly involving the left hemisphere is compatible with the fact that 81.2% of the study participants reported at follow-up to mainly use mobile phones on the right side but only 18.8% on the left side or with no laterality preference. Strikingly, our laterality analyses indicated indeed stronger associations for right side users for the figural memory task whereas the reverse pattern was seen for the verbal task. However, the sample size of the laterality analysis was small for the subgroup with left side or no side preference for mobile phone use (n= 80).

We considered a number of potential confounders and adjusted model estimates were relatively similar to the crude model estimates, which indicates that confounding seems not to have a substantial impact on the results. Nevertheless, we cannot exclude that we have missed a relevant confounder ....


The observed striking pattern with more consistent associations for RF-EMF dose measures compared to usage measures and no indications of associations for negative control exposure variables may indicate that RF-EMF exposure affects the figural memory of adolescents. However, given the complex correlation structure for various exposure measures and the uncertainty in the RF-EMF dose calculation, the observed associations need to be interpreted with caution.