Get the Facts

1. The available scientific evidence does not support an increased risk of malignant or benign brain/CNS cancers from cell phones.
   1. People are concerned that the widespread radiofrequency nonionizing radiation emitted by cell phones may cause brain/CNS cancers because cell phones are usually held close to the head.
   2. Cell phones emit non-ionizing radiofrequency (RF) radiation (low energy), which is different from ionizing radiation (high energy.
   3. Epidemiologic research has been carried out over many years by different experts in multiple countries using the best-designed scientific studies in very large numbers of people.
   4. Epidemiologic studies show no consistent evidence of an increase in malignant or benign CNS cancers in adults or children.
   5. The evidence from epidemiologic studies to date, as described below, does not support a relationship between cell phone use and brain or central nervous system (brain/CNS) cancers.
   6. Evidence from animal studies does not support an increased risk [insert link to Research Section].
2. Population incidence studies of brain/CNS tumors in large numbers of people do not support an increased risk.
   1. The number of cell phone users has increased greatly from the mid-1990s to the present.
   2. Population-based malignant brain/CNS cancer incidence rates (i.e., diagnosis of new cases in the entire population in a country or region) in adults and in children have not changed much for several decades in the U.S. and other countries. Nationwide, U.S. incidence rates for benign brain tumors in adults have been available since 2004, and these rates have been stable for more than a decade.
   3. Because the number of cell phone users and the amount of cell phone use have expanded greatly since the mid-1990s, if use of cell phones increased the risk of brain/CNS tumors, one would expect to see increasing rates of these tumors.
3. Cohort and case-control studies do not support an increased risk of cancer from cell phones.
   1. Cohort follow-up studies of large populations of adult cell phone subscribers (Denmark) or women self-reporting use (United Kingdom) have found no evidence of an increased risk of malignant or benign brain/CNS tumors with cell phone use. The COSMOS study enrolled over 250,000 people from several European countries, followed them for over 7 years, and found no indication that those who were heavier users of cell phones had a higher risk of cancer.
   2. The 13-country Interphone case-control study, which compared amount of cell phone use in cases to amount of use in controls, mostly showed no increases overall in brain/CNS malignant or benign brain tumors. One analysis showed a small increase in malignant brain/CNS cancers in people who spent the most time on cell phone calls, but the researchers interpreted this finding as inconclusive.
   3. Single country case-control studies in adults have reported inconsistent results for use of cell phones in relation to brain/CNS cancers.

i.A few studies have reported increased risk, which are clearly implausible given observed time trends in brain tumor cancer incidence (Ref: https://www.sciencedirect.com/science/article/pii/S0160412022004147).

ii.A limitation of case-control studies is retrospectively self-reported mobile phone use data.

1. It’s likely that some of the observed results are due to recall bias, meaning that cases have overestimated their mobile phone use compared to healthy controls.
2. Several studies provide indications for the presence of recall bias in these studies.
   1. Researchers have wondered if children using cell phones may be at greater risk of developing brain tumors than adults because their brain tissue is still developing, their heads are smaller than those of adults, and their brains have higher water content than the brains of adults. Experimental and mathematical studies suggest that about twice as much energy from exposures to cell phones is absorbed in the outer parts of children’s brain tissue compared to adults. Two international case-control studies of child/adolescent and adolescent/young adult brain tumors showed no increase in brain tumor risk related to use of cell phones.

Feychting M, Schüz J, Toledano MB, Vermeulen R, Auvinen A, Harbo Poulsen A, Deltour I, Smith RB, Heller J, Kromhout H, Huss A, Johansen C, Tettamanti G, Elliott P. Mobile phone use and brain tumour risk - COSMOS, a prospective cohort study. Environ Int. 2024 Mar 2;185:108552. doi: 10.1016/j.envint.2024.108552. Epub ahead of print. PMID: 38458118.

Röösli M, Lagorio S, Schoemaker MJ et al. Brain and salivary gland tumors and mobile phone use: Evaluating the evidence from various epidemiological study designs. Ann Rev Publ Health 2019;40:221-238. http://dx.doi.org/10.1146/annurev-publhealth-040218-044037

Frei P, Poulsen AH, Johansen C, et al. Use of mobile phones and risk of brain tumours: Update of Danish cohort study. BMJ 2011;343:d6387. https://doi-org.utk.idm.oclc.org/10.1136/bmj.d6605

Schuz J, Pirie K, Reeves GK, et al. Cellular telephone use and the risk of brain tumor: update of the UK Million Women Study J Natl Cancer Inst 2022;114(5):704-711. https://doi.org/10.1093/jnci/djac042

The Interphone Study Group. Brain tumour risk in relation to mobile telephone use: Results of the INTERPHONE international case-control study. Int J Epidemiol 2010;39(3):675-694. https://doi.org/10.1093/ije/dyq079

Aydin D, Feychting M, Schuz J, et al. Childhood brain tumors and use of mobile phones: comparison of a case-control study with incidence data. Environ Health 2012;May 20:11:35.https://doi.org/10.1186/1476-069X-11-35.

Castaño-Vinyals G, Sadetzki S, Vermeulen R, et al. Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids study. Environ Int 2022;160:107069

1. There are not enough data to determine whether cell phones cause cognitive and sleep disorders.
   1. Numerous human epidemiological studies have not found any consistent association between acute exposure to radiofrequency (RF) radiation from cell phones and cognition or self-reported sleep quality.
   2. There is insufficient evidence to provide a clear answer.
   3. There is limited epidemiological research on the impact of RF radiation exposure from cell phones on health problems such as cognitive issues (the conscious and unconscious processes involved in thinking, reasoning, and remembering) and sleep disorders.
   4. In contrast to epidemiology, numerous human experimental studies did not find any consistent association between acute exposure to RF radiation from cell phones and cognition or self-reported sleep quality.
2. Limited studies suggest that greater cell phone use by pregnant women and their children (including teenagers) is associated with some behavioral and emotional problems.
   1. There are some studies suggesting that a greater amount of cell phone use by pregnant women and their children, including teenagers, is associated with some behavioral and emotional problems.

ii.However, these studies cannot tell us whether observed associations are due to actual RF exposure from cell phones during pregnancy or other non-RF aspects related to cell phone use. Alternatively, heavy cell phone use by the mothers may be an indication of behavioral problems of the mother, which was inherited by their children.

1. 1. There are many more factors affecting the behavior of children that may be related to mobile phone use of the parents. It is a challenge to consider all these factors in observational research, which may have contributed to bias in these studies.
2. Demonstrating that the same relationship between exposure and health or behavioral effects exists in multiple studies is important to determine if an association is present.
   1. A problem in trying to draw conclusions from these studies is that they try to address many different exposures, including exposure during pregnancy to mothers, direct exposure to children, cell phone use, and residence or closeness to cell phone towers.

i.These studies have mostly been on children, with even less research on the potential impact of RF radiation exposure from cell phones on adult function.

ii.The range of health problems considered is also variable, including reduced sleep, emotional problems, and intellectual development.

1. 1. 1. Because of many different exposures and effects, there are few findings that have been reproduced.

1. There is no clear scientific evidence that RF exposures to persons living close to cell phone towers causes adverse health effects.
   1. Cell phones communicate with nearby cell towers mainly through radiofrequency (RF) signals.
   2. During a phone call, the RF signals (or waves) from a cell phone tower antenna are transmitted to and from the base station and decrease rapidly as the distance from the antenna increases. Consequently, the level of exposure at ground level is much lower than the level close to the antenna.
   3. Note that actual and cumulative RF EMF exposure contribution from own device use, operating close to the body is considerably higher than from cell phone towers.
2. Regulatory authorities such as the US Federal Communication Commission (FCC) set the limits for safe exposure to radiofrequency based on published scientific data.
   1. Experts (scientists and engineers) from two organizations, the National Council on Radiation protection and Measurements (NCRP) and the Institute of Electrical and Electronics Engineers (IEEE) extensively reviewed the scientific literature on the biological effects of the RF waves used in 5G and established safety guidelines, which have been strictly adopted by the US Federal Communication Commission (FCC).
   2. At ground level near typical cellular tower, the amount of energy from RF waves is usually hundreds to thousands of times less than that set by the US FCC.
   3. Within the recommended safety levels there should be no consequence to public health by living closer to 5G tower base stations.

Reference: https://www.cancer.org/healthy/cancer-causes/radiation-exposure/cellular-phone-towers.html

1. There is little research on childhood cancer risks from proximity to cell phone towers. The available scientific evidence does not support any increased risk of childhood cancer from residential proximity to TV and radio broadcast towers that emit radiofrequency and other frequencies of electromagnetic fields.
   1. Researchers have wondered if children living near cell phone towers may be at greater risk of developing leukemia, brain, or other cancers than adults because their brain tissue is still developing, their heads are smaller than those of adults, and their brains have higher water content than the brains of adults. Experimental and mathematical studies suggest that about twice as much energy from exposures to cell phones is absorbed in the outer parts of children’s brain tissue compared to adults. There is little research on childhood cancer risks from proximity to cell phone towers, but the few studies examining childhood cancer risks among those living in proximity to TV and radio broadcast towers suggest no association. The type of radiation produced by cell phone towers cannot damage DNA, and the only known effect is a tiny amount of heating of the brain.
   2. Radiofrequency exposures fall dramatically with increased distance from cell phone towers; even exposures close to cell phone towers are lower than the radiofrequency exposures from using cell phones.
   3. Public access to cell phone towers is restricted and towers have posted warning signs.

1. It is unlikely that radiofrequency emitted from fifth generation (5G) cell tower base stations will affect our health.
   1. Fifth generation (5G) radiofrequency (RF) waves are a form of energy that does not cause damage to the DNA of cells. The only established effect is a tiny heating of the tissue.
2. 5G can transmit much larger amounts of data over shorter periods of time compared to previous generations (4G, 3G, etc.).

a. 5G cellular networks are replacing older cellular networks because 5G can transmit much larger amounts of data over shorter periods of time compared to previous generations (4G, 3G, etc.).

The higher frequency is penetrating less into buildings and into the body. Thus, in that respect exposure levels are expected to be lower. In the near future, substantially higher frequencies will be used (24-80 Ghz). In this case, communication will only work with direct line-of-sight conditions. This implies that the network will be designed in a manner that people are rarely exposed, since this would block the communication. This type of radiation will also not penetrate buildings unless a receiver is installed that bridges the wall and window.

1. Within the recommended safety levels there should be no consequence to public health by living closer to 5G tower base stations.
   1. Experts (scientists and engineers) from two organizations, the National Council on Radiation Protection and Measurements (NCRP) and the Institute of Electrical and Electronics Engineers (IEEE) extensively reviewed the scientific literature on the biological effects of the RF waves used in 5G and established safety guidelines, which have been strictly adopted by the US Federal Communication Commission (FCC).
   2. When the recommended safety levels are observed, there should be no consequence to public health by living closer to 5G tower base stations.

1. No, adding base stations usually includes reducing the power of each station.
   1. No, because when additional base stations are added, the overall transmit power of each station is usually reduced. This is because cellular communications are not typically limited by signal strength, but by the presence of interference.
   2. Cellular providers want to reduce the power that their base stations transmit so that they can re-use their (expensive and scarce!) radio spectrum in more parts of their network. Thus, the average exposure from base stations for cell phone communication does not depend strongly on the number of base stations present. Nevertheless, as a net effect exposure from base station may increase on average.
2. The main source of RF exposure is the cell phone itself.
   1. Cell phone communication is two-way. Both your cell phone and the cell tower are transmitting and receiving radiofrequency (RF) signals.
      1. Like all electromagnetic energy, RF signals get weaker the further you get from the source.
      2. The greater the distance a cell phone is from an antenna, the greater the power the cell phone needs to use for its signal to reach the tower.
      3. There is more RF exposure to cell phone users when cell towers are widely spaced. This can be up to a factor of a million in terms of output power. When phone users are close to towers, the cell phone uses less power to emit its signal, which means less RF exposure to the cell phone user. Your total exposure to RF is due primarily to your own phone’s emissions — an exposure that actually increases when the cell towers get farther apart.
      4. This means that in a dense network actual and cumulative RF-EMF exposure of the population is decreasing

Reference: Applied Sciences | Free Full-Text | Total Local Dose in Hypothetical 5G Mobile Networks for Varied Topologies and User Scenarios

1. Yes, walls and windows reduce the signal inside the building.
   1. In urban areas, cell phone antennas are usually installed on the edge of rooftops or the sides of buildings. Radiofrequency (RF) energy from these antennas is directed horizontally, although often with some sort of mechanical and electrical down tilt in the radiation pattern. Walls and windows reduce the signal for people inside the building. Tinted windows are especially good at reducing RF power levels (by more than a factor of 10) and often reduce RF power levels even more than a solid exterior wall due to the metal in the tinting.
2. Walls and windows are even more effective at damping 5G signals.
   1. With 5G and the use of higher frequencies, the damping by walls and windows will be even more efficient than in the past. A person standing outdoors at street level may experience higher field strengths than someone indoors whose window is at the same height as a base station antenna.
   2. In either case, the RF power density for the person will meet all current RF safety guidelines.

1. No mechanisms from modulation that could cause adverse health effects have been established.
   1. Numerous experimental studies have tested various types of modulation. Whereas different effects according to modulation have been occasionally described on the level of a single study, no overall pattern was observed over all studies. This indicates that single study results are most likely chance findings arising from testing multiple exposure conditions.
2. Modulation and pulsation of cell phone, WiFi and Bluetooth radiation is relatively weak.
   1. It is well established that very strongly modulated fields like from radar can have distinct biological effects such as microwave hearing. However, such effects cannot occur and have not been observed to occur for exposure from cell phones or WiFi, which are less strongly modulated.

Reference: Stefan Dongus, Hamed Jalilian, David Schürmann & Martin Röösli (2022) Health effects of WiFi radiation: a review based on systematic quality evaluation, Critical Reviews in Environmental Science and Technology, 52:19, 3547-3566, DOI: 10.1080/10643389.2021.1951549

Reference: Foster KR and Repacholi MH. Biological effects of radiofrequency fields: Does modulation matter? Radiation Research, 162: 219-225, 2004. https://doi-org.utk.idm.oclc.org/10.1667/RR3191

1. EMF-RF exposures cannot damage DNA and cause only slight heating of the brain.
   1. Researchers have wondered if children exposed to cell phones may be at greater risk of developing brain tumors than adults because their brain tissue is still developing, their heads are smaller than those of adults, and their brains have higher water content than adults, resulting in increased heating.
   2. Experimental and mathematical studies suggest that about twice as much energy from exposures to cell phones is absorbed in the outer parts of children’s brain tissue compared to adults. However, the type of radiation produced by cell phones cannot damage DNA, and the only known effect is a tiny amount of heating of the brain.
2. Two different studies in multiple countries found no increase in brain tumors.
   1. Two case-control studies of cell phone use and brain tumors in children have found no increase in risk by amount of use of cell phones, and the location of brain tumors in children is not related to where cell phones are held against the head.
   2. Both of these studies were carried out in multiple centers in several countries (the earliest in 4 countries involving 352 cases and 646 controls ages 7-19 and the most recent in 14 countries involving 899 cases and 1910 controls ages 10-24 years old), used detailed questionnaires, examined the location of the brain tumor in relation to use of the cellular phones, examined the potential for recall bias comparing self-reported with objective cell phone use data and examined the potential for confounding.
   3. Despite the multi-center, multi-country nature of both studies, the rarity of brain tumors made it difficult to identify small risks (particularly according to age, type of brain tumor, location of the tumor in the brain), and the use of questionnaires does not capture the actual exposure in the brain.

References:

1. Aydin D, Feychting M, Schuz J et al. Mobile phone use and brain tumors in children and adolescents: a multicenter case-control study. J Natl Cancer Inst 2011;103:1264-1276. https://doi.org/10.1093/jnci/djr244
2. Castano-Vinyals G, Sadetzki S, Vermeulen R, et al. Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids Study. Environ Int 2022;160:107069. https://doi.org/10.1289/isee.2022.P-1070
3. Kheifets L, Repacholi M Saunders R et al. The sensitivity of children to electromagnetic fields. Pediatrics 2005;116:e303-313. https://doi-org.utk.idm.oclc.org/10.1542/peds.2004-2541
4. Christ A, Gosselin MC, Christopoulou M et al. Age-dependent tissue-specific exposure of cell phone users. Phys Med Biol 2010;55:1767-1783.https://doi.org/10.1088/0031-9155/55/7/001
5. Wiart J, Hadjem A, Wong MF et al. Analysis of RF exposure in the head tissues of children and adults. Phys Med Biol 2008;53:3681-3695. http://dx.doi.org/10.1088/0031-9155/53/13/019

1. For radiofrequency (RF) fields from cell phone and cell towers, there is no indication of any increased risk related to exposure.
   1. Fetuses are known to be at risk of health effects from environmental exposures, such as lead and some drugs, so it is reasonable to ask whether it may be a period of sensitivity to RF radiation exposure.
   2. A few studies have looked at the effect of RF exposure on the health of pregnant women and fetuses, assessing outcomes such as miscarriage, preterm birth, or birth defects. These studies did not find any adverse effects.
   3. In summary, there is very little relevant research but no scientific basis to be concerned about exposures during pregnancy.

1. Generally, less energy is absorbed from the earbuds (e.g., AirPods) for the same usage time as a cell phone.
   1. There should be considerably less power absorbed by your head when you use an earpiece such as earbuds, as compared to holding a cell phone to your ear.
   2. However, the overall duration of exposure might be longer, simply because hands-free earpieces encourage some people to increase the number and length of their phone conversations!
2. Earbuds transmit at an average power level ten times lower than a cell phone. a. During a call an earpiece, such as an AirPod, will significantly reduce the Specific Absorption Rate (SAR) — a key safety metric.
   1. AirPods and similar devices use a 2.4 Gigahertz Bluetooth low-energy link to communicate with the nearby handset, so they are emitting radiofrequency (RF) signals that are similar in frequency to the UHF or microwave signals that the cell phone emits to communicate with a base station.
   2. However, these Bluetooth links transmit at an absolute maximum power level of 100 milliwatts (mW), which is about 10 times less, on average, than a typical cell phone.

1. WiFi provides a small contribution to total RF exposure.
   1. Exposure to children or adults from wireless local area networks (WiFi), whether in schools, public buildings, or at home, is common but is only a small contributor to RF radiation exposure overall.
   2. WiFi is estimated to contribute less than 10% of total RF exposure. Because it is thousands of times lower than the regulatory limits it is not expected to have any adverse effects on health.
2. Studies find no indication of harmful effects on sleep, fatigue, or behavioral problems.
   1. Personal measurement studies could not find any relevant difference in possible effects of the RF-EMF exposures of children in relation to the WiFi conditions at home or at school.
   2. There are few laboratory studies or studies on humans exposed to WiFi. Those that have been done do not provide any meaningful support for sleep disturbance, headaches or fatigue, or physiologic effects such as changes in blood pressure or heart rate.

Reference: Ref: Personal radiofrequency electromagnetic field exposure of adolescents in the Greater London area in the SCAMP cohort and the association with restrictions on permitted use of mobile communication technologies at school and at home - ScienceDirect

Personal radiofrequency electromagnetic field exposure measurements in Swiss adolescents - ScienceDirect

1. No, they may be used in any position the user desires.
   1. Cellphones may be used in any position with respect to the body that the user finds comfortable.
   2. The Federal Communications Commission (FCC) uses models of humans (phantoms) to test whether local radiofrequency (RF) exposure (measured as Specific Absorption Rate, SAR) of cellphones is within regulatory limits. SAR is a measure of the rate of energy absorption by the body.
   3. Cell phones are tested in a maximum output configuration even though the cellphones are not used that way by consumers. The FCC measures the radiofrequency output of cellphones next to the head or body, in the typical positions that people would use them.
   4. Two phantoms are used for this purpose. The first is a head phantom model where the cell phone is next to the ear when tested. The other is a body phantom used to mimic the location of the cellphone in body-worn accessory configurations. The area surrounding where a cell phone is carried or used cannot have a local SAR greater than 1.6 Watts per kilogram.
   5. There is a 10-fold safety factor between the regulatory SAR limit and actual health risk. Thus, even if the phone is held closer to the body and absorbed SAR would be above 1.6 W/kg it still would not reach the 40 W/kg, that may be a health risk in the long run.

Further Reading

https://www.fcc.gov/consumers/guides/specific-absorption-rate-sar-cell-phones-what-it-means-you

Specific Absorption Rate (SAR) Testing | UL

1. Yes, RF exposure from cellphones kept close to your body does not cause illness or injury.
   1. Carrying your cellphone in your bra or pants pocket might not be comfortable or hygienic, but the radiofrequency exposure from carrying the phone close to your body does not cause illness or injury.
   2. Cellphones seldom operate at their maximum RF output, but they are tested at their maximum output. Even in that mode of operation they may not exceed a Specific Absorption Rate (SAR) of 1.6 Watts per kilogram. When the phone is up against the skin and operating at maximum output the maximum local SAR does not exceed 1.6 Watts per kilogram.

Further Reading

https://www.nationalbreastcancer.org/breast-cancer-myths/carrying-a-phone-in-your-bra-can-cause-breast-cancer/

1. The National Toxicology Program (NTP) studied cell phone exposures in rats and mice.
   1. In 1999 the U.S. Food and Drug Administration (FDA) recommended that studies be undertaken in animals of radiofrequency radiation used in 2G and 3G cell phones due to widespread public use of cell phones and limited knowledge about health effects from long-term exposure.
   2. The National Toxicology Program (NTP) conducted two-year studies in rats and mice that were initiated during pregnancy for rats and within a few weeks after birth for mice. The numbers of animals studied included ninety exposed and ninety unexposed rats, and the same numbers of mice. These animals were exposed for 9+ hours daily with exposures on for 10 minutes and off for 10 minutes during those hours.

2.The NTP study found no increase in all cancers studied except for a small increase in rare tumors, and only in male rats.

1. 1. The NTP researchers summarized the findings as showing that only one of the groups studied, exposed male rats, had a statistically significant increased risk of cancerous heart tumors, called malignant schwannomas, with increasing levels of radiofrequency radiation exposures.
   2. The NTP studies also observed some evidence of tumors in the brain and adrenal gland in male rats, although the evidence was not as strong as what was observed in the heart.
   3. For female rats and male and female mice, there was no statistically significant increases of these, or other types of cancers related to cell phone radiofrequency radiation.
   4. There has been no evidence of an increase in these rare tumors in humans.
2. NCRP and other expert groups consider the results inconclusive due to study limitations.
   1. The interpretation of the conclusions from the studies has been debated among scientists.
   2. Also, humans do not experience malignant schwannomas of the heart, and therefore it is difficult to generalize the findings from the male rats to humans.
   3. NCRP considers the results to be inconclusive and not supportive of increased risk of cancer in humans.
   4. NCRP’s conclusion was based on (1) inconsistencies between the findings for male versus female rats and between male rats and mice; (2) lack of any tumors in the control rats even though some would have been expected based on previous studies; (3) shorter survival of male control rats than male exposed rats, thus reducing the possibility of that late-onset tumors could arise; (4) review of the tumor and other pathology by pathologists who knew which tissues belonged to exposed animals and which belonged to unexposed animals; (5) lack of use of statistical methods to account for the many statistical comparisons that possibly resulted in randomness or chance as an explanation for the results.
   5. In addition, the exposures were to the whole body of the animals, whereas cell phone exposures of concern are to the head.
   6. The NTP study focused on 2G and 3G and therefore it is difficult to generalize the findings to those radiofrequency exposures of 4G in widespread use for several years and more recently 5G.
   7. Strengths of the studies:

• the most comprehensive evaluation to date of health effects in animals exposed to radiofrequency radiation as used in 2G and 3G cell phones.
• a wide range of different types of cancers and non-cancer health effects were studied,
• two different types of animals were studied.
• the researchers reported all details of the study methods.
• the researchers provided a detailed description of the exposure which included high, medium and low levels of exposure.
• high-quality engineering and materials were used in the laboratory where the study was carried out.
• careful expert pathology review of tissues was undertaken.
  1. Limitations of the studies (in addition to the points listed above):

• no temperature measurements, but strong evidence of the potential for stress leading to raised body temperatures in the high-dose group of animals.
• relatively small group size in each exposure group, particularly when small risks are considered.
• only one control group for each type of animal studied.
• other methodological and statistical issues as discussed in the references below of the International Commission on Non-Ionizing Radiation Protection (2020) and Vijayalaxmi et al (2020).

References:

National Toxicology Program. Toxicology and carcinogenesis studies in Hsd:Sprague Dawley SD rats exposed to whole-body radiofrequency radiation at a frequency of (900 MHz) and modulations (GSM and CDMA) used by cell phones. Research Triangle Park, NC: National Toxicology Program; NTP TR-595; 2018a. https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/lt_rpts/tr595_508.pdf

National Toxicology Program. Toxicology and carcinogenesis studies in B6C3F1/N mice exposed to whole-body radiofrequency radiation at a frequency of (900 MHz) and modulations (GSM and CDMA) used by cell phones. Research Triangle Park, NC: National Toxicology Program; NTP TR-596; 2018b. https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/lt_rpts/tr596_508.pdf

International Commission on Non-Ionizing Radiation Protection (ICNIRP). ICNIRP Note: Critical evaluation of two radiofrequency electromagnetic field animal carcinogenicity studies published in 2018. Health Phys 2020;118(5):525-532. https://doi.org/10.1097/HP.0000000000001137

Vijayalaxmi, Foster KR, Miyakeshi J, Verschaeve L. Comments on the evaluation of the genotoxicity of cell phone radiofrequency radiation in male and female rats and mice following subchronic exposure by Smith-Roe et al. Environ Mol Mutag 2020;61(s):291-293. https://doi-org.utk.idm.oclc.org/10.1002/em.22353

1. The International Agency for Research on Cancer (IARC) conducts comprehensive reviews by experts of chemical and physical agents.
   1. The International Agency for Research on Cancer (IARC) is part of the World Health Organization.
   2. IARC conducts comprehensive reviews of a wide range of chemical and physical agents that may cause cancer.
   3. For its comprehensive reviews, IARC assembles large committees of appropriate experts in many fields to review all published studies on a given agent and decide whether the agent is a cause of cancer.
   4. The committee then votes on a decision about the results of the entire group of studies as to whether the results support or do not support the agent as a cause of cancer.
2. IARC experts vote on their conclusions from the review and assign a category.
   1. IARC uses the following classification system as options for each committee’s decision.

• Group 1: sufficient evidence that the agent causes cancer.
• Group 2A: evidence that the agent is a probable cause of cancer.
• Group 2B: evidence that the agent is a possible cause of cancer.
• Group 3: insufficient evidence that the agent is a cause of cancer.
• Group 4: there is evidence suggesting that the agent does not cause cancer.

1. IARC classification 2B: limited evidence associating cell phone use with brain tumors
   1. In 2011, 30 experts reviewed all available evidence on radiofrequency exposures with a major focus on cell phones.
   2. A majority of the committee concluded that radiofrequency exposure is a possible cause of cancer in humans.
   3. Since 2011 some additional studies have been published including a large cohort study reporting no evidence of increased brain tumor risks. As further research is done, IARC may revise its assessment based on additional evidence.

1. The only potential health effect of radiofrequency (RF) electromagnetic radiation (EMR) on humans with any clear cause and effect is tissue heating.
   1. The scientific literature has discussed the potential health effects of radiofrequency (RF) electromagnetic radiation (EMR) on humans with no clear cause and effect except tissue heating above a safety limit established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
2. Many animal studies have been completed and do not conclusively support and biological effect other than tissue heating.
   1. Some investigations observe potential effects of RF EMR in the tissues and organs of live animals like mice, rats, and rabbits below this limit. These animals exposed to RF EMR have been observed for evidence of cancer, neurological abnormalities, reproductive abnormalities as well as DNA damage, and other changes in metabolism. Many of these investigations are small observational studies that use RF exposure equipment of questionable utility, have quality control issues or problems with investigator blinding during data analysis. Overall, the in vivo studies to date do not support RF biological effects other than tissue heating above the ICNRP safety limit.
   2. One of the best controlled and largest in vivo study was performed by the National Toxicology Program (NTP) in rats and mice (1). The three components of the NTP study were a 5-day thermal pilot study at specific absorption rates (SARs) of 4-12 W/kg, a 28-day toxicology study in mice and rats and a 2-year carcinogenicity and toxicology study in mice and rats. A specifically designed reverberation chamber was used to provide nearly uniform whole-body exposure without use of animal restraint. The rats and mice were exposed to one of the two types of cellphone communication systems in use throughout the world. Global system communication (GSM) or code division multiple access (CDMA) modulations for 18 hours and 20 minutes per day, 10 minutes on and 10 minutes off. The rats were exposed to either a GSM- or CDMA- modulation signal at 900 MHz and the mice either a GSM- or CDMA- modulation signal at 1900 MHz. The five-day thermal pilot study examined the impact of animal size on subcutaneous temperature in rats and mice and pregnant rats up to 270 days in age. There were some instances of increased subcutaneous temperatures (>1⁰C) in older rats exposed to 6 W/kg GSM RFR or 900 MHz CDMA RFR but not in young rats. There were sporadic temperature increases in young and old mice exposed up to 12 W/kg, Temperature measurements were made with the RFR off so skin cooling may have reduced the measured superficial temperature. Aged and pregnant rats were shown to have more difficulty regulating temperature during RFR exposure. However, temperature was only measured up to 270 days and rats and mice in the NTP study were RFR exposed up to 2 years. The micronucleus assay and the comet assay were used to assess genetic effects in RF-exposed mice and rats. There was a non-statistically significant increase in DNA damage in male rats exposed to CDMA RFR. There was no statistically significant increase in DNA damage observed in female rats or either mouse sex. All the results of the micronucleus assay in rats and mice were negative. According to the authors, the two-year carcinogenesis and toxicology study showed what the authors feel was clear evidence of carcinogenic activity for malignant schwannoma in the heart of male rats exposed to either GSM- and CDMA-modulations and some evidence of carcinogenic activity for malignant glioma in the brain of male rats and incidences of pheochromocytoma in the adrenal medulla of male rats exposed to GSM- modulation. A statically significant increase in the number of schwannomas of the heart was found in the highest exposure in male rats exposed to the CDMA-modulation and statistically significant trends in schwannoma incidence were reported as a function of exposure magnitude in both CDMA and GSM-modulations. The sham GSM exposed control male rats had zero schwannomas and the exposed rats had 2, 1, and 5 schwannomas in the 1.5, 3 and 6 W/kg groups. CDMA exposed male rats had 0, 2, 3 and 6 schwannomas in the sham control, 1.5, 3, and 6 W/kg groups respectively. There were no findings in female rats and either sex of mice. NTP reported a non-statistically significant increased incidence of malignant glioma in the brain male rats in both CDMA- and GSM-modulations. The 6 W/kg RFR exposures used in the NTP study is 75 times higher than the FCC limit (0.08 W/kg) and the mice and rats exposed to RFR over their whole body unlike the partial body exposure for people when they use cell phones.
   3. In vivo studies have used a variety of animal models to examine the impact of RFR on animal tissues. Most of the in vivo studies have exposed rats and mice to RFR and examined their tissues for biochemical, biological, or histological effects. Cancer development is the most widely studied endpoint. The cancer development studies vary in size, RF exposure methods, tissue types examined and endpoints. The two largest studies are the NTP study (1) summarized above and a study by Falcioni et al. (2). Like the NTP study, Falcioni et al. (2) followed good laboratory practice and studied a larger sample of whole-body exposed rats. Four hundred male and female rats were whole body exposed to 1.835 MHz GSM-modulated external fields. The external fields were equivalent to whole-body SARs of 0, 0.001, 0.03 and 0.1 W/kg. These SARs were much less than the SARs used in the NTP study and only one exposure (0.1 W/kg) was greater than the ICNRP safety limit of 0.08 W/kg for the public. Falcioni et al. (2) reported malignant schwannomas at a SAR of approximately 0.1 W/Kg as compared to the NTP study which reported statistically significant (p<0.05) number of malignant schwannomas with CDMA exposures at 6.0 W/kg. The Falcioni et al. (2) study and the NTP study are difficult to reconcile to determine if RF exposure is carcinogenic. Faliconi et al. (2) has statistically significant data at 0.1 W/kg for the GSM modulation and the NTP study has no statistically significant GSM modulation data. Only at 6.0 W/Kg CDMA exposures is there statistical significance. None of the Falcioni et al. (2) glioma incidence was reported to be significant.
   4. Other investigators have also examined whether RF exposure results in cancer. Two studies are discussed below. Lee et al. (3) used mice that spontaneously develop lymphoma to investigate whether RF exposure increases lymphoma incidence. The animals were exposed for 45 minutes per day for 5 days a week for 42 weeks at a SAR of 2 W/kg. No significant effect of RF exposure was detected on the incidence of lymphoma, survival time or weight. Jin et al. (4) used two combined modulations (849 MHz CDMA and 1950 MHz WCDMA) at a SAR of 4 W/kg rats for 45 minutes per day for a year. There were no significant effects on animal weight or spontaneous tumor development. While some investigations claim RF exposure can induce tumors and other investigation claim RF exposure does not induce tumors, much of the research has methodological problems such as not being conducted under GLP conditions, unblinded analysis, inadequate RF exposure systems, or the inconsistent animals exposed. Taken together, all the in vivo studies do not support carcinogenesis of RF exposure.

References

1. Wyde M, Cesta M, Blystone C, Elmore S, Foster P, Hooth M, Kissling G, Malarkey D, Sills R, Stout M, Walker N, Witt K, Wolfe M, Bucher J. Report of the partial findings from the National Toxicology Program carcinogenesis studies of cell phone radiofrequency radiation in Hsd: Sprague Dawley SD rats whole body exposure). BioRxiv 055699 (preprint 26 May 2016, modified 1 February 2018 (online). https://doi.org/10.1101/055699
2. National Toxicology Program. Toxicology and carcinogenesis studies in Hsd: Sprague Dawley SD rats exposed to whole body radio frequency radiation at a frequency (900 MHz) and modulations (GSM and CDMA) used by cell phones. Research Triangle Park, NC: National Toxicology Program; NTP TR-595; 2018.

https://doi.org/ 10.22427/NTP-TR-595

1. National Toxicology Program. Toxicology and carcinogenesis studies in B6C3F1/N mice exposed to whole-body radiofrequency radiation at a frequency (1900 MHz) and modulations (GSM and CDMA) used by cell phones. Research Triangle Park, NC: National Toxicology Program; NTP TR-596; 2018. https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/lt_rpts/tr596_508.pdf
2. National Toxicology Program. Actions from peer review of draft NTP technical reports on cell phone radiofrequency radiation, March 26-28, 2018. https://ntp.niehs.nih.gov/sites/default/files/ntp/about_ntp/trpanel/2018/march/actions20180328_508.pdf
3. Falcioni L, Bua L, Tibaldi E, Lauriola M, De Angelis L, Gnudi F, Mandrioli D, Manservigi M, Manservisi F, Manzoli I Menghetti I, Montella R, Panzacchi S, Sgargi D, Strollo V, Vornoli A, Belpoggi F. Report of final results regarding brain and heart tumors in Sprague-Dawley rats exposed from prenatal life until natural death to mobile phone radiofrequency field representative of a 1.8 GHz base station environmental emission. Environ Res 165:496-503: 2018. https://doi.org/10.1016/j.envres.2018.01.037
4. Lee H, Jin Y, Lee J, Choi S, Kim T Pack J, Choi H, Kim N, Lee Y. Lymphoma development of simultaneously combined exposure to two radiofrequency signals in AKR/J mice. Bioelectromagnetics, 32, 485-492; 2011, https://doi-org.utk.idm.oclc.org/10.1002/bem.20655
5. Jin Y, Lee, H, Seon Lee J, Pack J, Kim N, Lee Y. One-year, simultaneous combined exposure of CDMA and WCDMA radiofrequency electromagnetic fields to rats. International Journal Radiation Biology, 87(4), 416-23; 2011. https://doi-org.utk.idm.oclc.org/10.3109/09553002.2010.537428
6. Foster KR. Thermal and Nonthermal Mechanisms of Interaction of Radio-Frequency Energy with Biological Systems. IEEE Transactions on Plasma Sci. 28: 15-23, 2000. https://doi.org/10.1109/27.842819

Further Reading

1. Scientific Committee on Emerging and Newley Identified Health Risks. SCENIHR opinion on potential health effects of exposure to electromagnetic fields (EMF), 27 January 2015. https://health.ec.europa.eu/publications/potential-health-effects-exposure-electromagnetic-fields-emf_en
2. Health Council of the Netherlands. Mobile phones and cordless phones and cancer: part 3. Update and overall conclusions from epidemiological and animal studies. The Hague: Health Council of the Netherlands; Publication 06; 2016. https://www.healthcouncil.nl/documents/advisory-reports/2016/06/01/mobile-phones-and-cancer-part-3-update-and-overall-conclusions-from-epidemiological-and-animal-studies
3. Swedish Radiation Safety Authority. Recent research on EMF and health risk- twelfth report from SSM’s scientific council on electromagnetic fields (online) 2018.https://www.stralsakerhetsmyndigheten.se/publikationer/rapporter/stralskydd/2018/201809/

1. Regulations on exposure limits to RF vary among countries and even local governments.
   1. These regulations typically set exposure limits for i) equipment that operate with static fields (e.g., mobile devices, medical equipment like MRI), ii) electric appliances that use extremely low frequency electric and magnetic fields (50/60 Hz), and iii) various wireless, telecommunications and broadcasting equipment that use high radiofrequency electromagnetic fields (100kHz-300 GHz).
2. In general, policies and recommendations put into place at the national level focus on protecting the public.
   1. Examples include setting exposure limits that reduce personal exposure and restrictions of usage for certain potentially more sensitive populations like children and pregnant women.
   2. From a health risk perspective, we are generally interested in how much electromagnetic field power is absorbed by biological tissues, and this is described by the “specific absorption rate” (SAR), which is the power absorbed per unit mass (measured in W/kg). Exposure limits vary from country to country, mostly in the range of 0.08 to 2 W/kg.
   3. The WHO Global Health Observatory has an easy online tool to find guidelines and limits in various countries for a variety of indicators related to electromagnetic fields.

https://www.who.int/data/gho/data/themes/topics/topic-details/GHO/electromagnetic-fields

1. The scientific literature concerning the possible impact of 5G exposures is less extensive than for lower frequencies (4G and below)
   1. The introduction of the fifth generation (5G) of wireless communication will increase the number of high-frequency-powered base stations and thus possibly increase human exposure. Public concern now concerns whether higher frequencies (6–100 GHz, millimeter waves, MMW) can have a health impact. However, the scientific information available now on the impact of 5G exposure in animals and humans is not as extensive as that in lower frequencies (< 5G).
2. Existing studies show some response to exposure, but not enough quality information to perform an adequate safety assessment.
   1. Simko and Mattsson (2019) reviewed and analyzed 94 relevant in vivo or in vitro publications. The studies included study type (in vivo, in vitro), biological material (species, cell type, etc.), biological endpoint, and exposure (frequency, exposure duration, power density) and quality criteria. b. The results showed that 80% of the in vivo studies and 58% of the in vitro studies showed some response to exposure. However, there was no consistent relationship between exposure effects and power density and exposure duration. Thus, the available studies do not provide adequate and sufficient information for a meaningful safety assessment of 5G wireless communication. The authors suggested that the quality of investigations is important for future studies to be useful for safety assessment.

3. Many of the studies are vulnerable to non-replicable results.

References
Simkó M and Mattsson M-O. 5G Wireless communication and health effects. A pragmatic review based on available studies regarding 6 to 100 GHz. Int J Environ Res Public Health: 16 (18), 3406, 2019. https://doi.org/10.3390/ijerph16183406

Foster KR and Vijayalaxmi. Needed: More reliable bioeffects studies at “High Band” 5G frequencies. Frontiers in communications and networks. 2: 721925. https://doi.org/10.3389/frcmn.2021.721925

1. RF exposure is millions or billions of times less from the base station than from the mobile device being used.
   1. The RF exposure from a 5G cellular base station is less frequent, but more intense than lower frequency cellular base stations.
   2. Lower frequency cellular base stations will blanket a region of coverage with RF signals such that transmissions meant for a specific user are received by nearly everyone in the region.
   3. To support higher information data rates, mm-wave 5G cellular base stations focus their energy and roughly track its communicating user devices. That means other people in the coverage region do not experience much incidental RF exposure.
   4. Even when focusing on a user, the amount of RF exposure that a person experiences from the base station is millions or billions of times less than the exposure from a small, low-powered mobile device that they use to communicate with the base station.

1. Questions have arisen as to whether funding sources have influenced research studies.
   1. There has been an ongoing debate and discussion in scientific and public meetings - whether the source of funding influenced the outcome of research on human health effects of exposure to radiofrequency (RF) energy.
   2. In a systematic review, Huss et al (2007) concluded that “the interpretation of results from studies of health effects of radiofrequency radiation should take sponsorship into account.” The observations in a more recent review by Vijayalaxmi and Prihoda (2019) were:
      1. A great majority of researchers had acknowledged government agencies as the funding source while a small number of scientists mentioned the mobile phone industry as the financial source. Numerous investigators did not mention the source of funding.

ii.Industry-funded investigations tended to be of better quality and utilized quality control measures, i.e., blind evaluation, adequate description of dosimetry, positive controls and/or sham-exposed controls, compared with those funded by government agencies.

iii.Industry-funded investigations had a higher percentage of studies that reported no difference in genetic damage between the cells exposed to RF energy and sham-exposed controls compared with those funded by the government agencies.

iv.Industry-funded studies were less likely to report an increase in genetic damage in cells exposed to RF energy compared with those funded by the government agencies.

1. 1. Overall, it is important for publications to describe the quality control measures used in the investigations and to mention the source of funding.
2. Some evidence suggests bias in both directions may occur.
   1. An important finding of Huss et al was that bias in both directions was observed including bias in studies without funding and bias in industry-funded studies.
   2. To prevent bias, some funders with potential interests in the study outcome have implemented a firewall. This means that the study sponsor is not in direct contact with the researcher and that the contract and payment is made by a 3rd party. No bias was seen in studies based on mixed funding or when applying firewalls, and the quality of these studies was significantly higher.
   3. In view of the significant difference between the percentage of publications funded by government agencies and industry, the above observations should be debated/discussed with caution. Overall, it is important for publications to include the quality control measures used in the investigations and to mention the source of funding. Note that the number of health studies funded by industry has considerably reduced in the last 15 years.

References:

Huss A, Egger M, Hug K, Huwiler-Muntener, Roosli M. Source of funding and results of studies of health effects of mobile phone use: Systematic review of experimental studies. Environ Health Persp. 2007; 115: 1-4, 2007. https://doi.org/10.1289%2Fehp.9149

Vijayalaxmi and Prihoda TJ, Funding Source, Quality of Publications and Outcome in Genetic Damage in Mammalian Cells Exposed to Non-Ionizing Radiofrequency Fields. Rad Res. 193, 353-362, 2019. https://doi.org/10.1667/RR15364.1

Van Nierop L.E., Röösli M., Egger M., Huss A. Source of funding in experimental studies of mobile phone use on health: Update of systematic review. Comptes-Rendus Physique de l’Académie des Sciences, 2010, 11 (9-10): 622–627. https://doi.org/10.1016/j.cthy.2010.10.002

1. Defender shields are designed to prevent RF from penetrating beneath a laptop
   1. The term “defender shield” typically refers to a protective mat placed beneath a laptop, standing tablet, or mobile device to shield the electromagnetic radiation and/or flow of heat. These shields contain metal that prevent radio waves from penetrating the surface beneath a wireless device.
2. Most wireless devices, including laptops, emit fields to the side, not downward
   1. Defender shields certainly perform this function, but most wireless devices are designed to radiate laterally.
   2. Most laptops, for example, have their antennas integrated into the screen. When the laptop is in use, the screen is raised, and the integrated antennas are mostly radiating outwardly toward the horizon.
   3. There is not much reduction by the defender shield in the radiated power experienced by the laptop user.
3. All devices will have been certified to emit biologically safe levels of RF power
   1. Regardless of whether the shield is used or not, the amount of radiated energy that reaches a user from the laptop in this scenario is many times less than a wearable device or mobile device in a person’s pocket.
   2. In all cases, the device will have been certified to emit biologically safe levels of electromagnetic power.

1. No consistently identified adverse effects at typical RF levels
   1. With any exposure to physical (or chemical) agents, there is always some possibility of unexpected effects on health, and for that reason, there is a need for research which would uncover such problems if they occurred.
2. Research continues to assess the possibility of harm
   1. While it can never be claimed that there is absolutely no possibility of unrecognized harm, in the case of radiofrequency exposure, health effects would not be expected based on the physical characteristics of the exposure. Also there has been extensive research that has looked at that possibility and has not found evidence of harm.
3. Widespread RF exposure with no identified harm makes it unlikely effects will be found
   1. Research on cells, animals, and humans taken together suggests that at exposure levels present in the environment, home, workplace, and medical settings, there is not an identifiable effect on health, and it is unlikely to be found in the future. Nonetheless, because exposure is so widespread, the research should and will continue to explore all possible harmful effects of radiofrequency exposure.

1.Some isolated suggestions of harm, but no consistent, reproducible evidence

1. 1. When there are multiple studies addressing the same question, it is common for there to be a range of findings, including some that raise the possibility of there being harmful effects. But to draw conclusions, it is essential to consider all the evidence. Even within a single study, there may be a mix of findings, and in the case of radiofrequency exposure, this may include some suggestions of possible harm to health. When isolated studies or findings are overemphasized, this is sometimes referred to as “cherry picking.”
   2. There are scattered studies of health effects of radiofrequency exposure that would suggest potential harm to health if looked at in isolation, but not when combined with the results of other studies on the same topic. All studies have limitations and the possibility of producing inaccurate results, which is why we need to replicate findings to draw conclusions.
   3. Given how important this issue is because of widespread exposure and public concern, suggestions of possible health effects tend to be followed up quickly and when that has been done, it has generally put the issue to rest. There will continue to be studies of health effects of radiofrequency exposure, and some of those studies will undoubtedly find some indications of possible harm. But only if such leads are confirmed with more extensive, rigorous research would it change the overall weight of the evidence.
2. A suggestion of a biological response does not mean there is a threat to health
   1. In some instances, there are subtle biological responses to radiofrequency exposure, but that does not mean that there is a threat to health. There are subtle biological responses to a change in the temperature, being exposed to sunlight, or light exercise, but the important question is whether these changes suggest that there will be harm to health. In the case of radiofrequency exposure, that has not been found.
3. Reported effects of cell phone use may not be due to radiofrequency exposure
   1. Finally, it is worth noting that there are potential adverse effects of cell phone use independent of radiofrequency exposure. The link between cell phone use while driving and risk of motor vehicle injury is clear, for example, and there is a great deal of concern over the mental health impact of excessive use of cell phones for social media. Cell phone use at night has been associated with disturbed sleep, but not because of radiofrequency exposure.