How excessive cell phone usage can cripple a child’s mental development

The scene of a quiet child tapping away at a phone or tablet with glee is an image that, by now, most people are familiar with. It may seem cute at first, however a sinister reality lurks beneath this scenario. Overwhelming research now shows that excessive cell phone usage in infants and adolescents can slow down, or even permanently alter, various parts of their extremely sensitive and still growing brains. Social skills, cognitive abilities, and emotional awareness can all be affected. This technology is often incredibly addicting because of its constant bombardment of lights, colors, and rewarding sounds that can thus inhibit a child’s ability to focus, learn how to properly socialize with other humans, and develop an interest in other activities. We as a society should be more aware of the effects that our phones have on our children so that we do not end up altering the biology of an entire generation. It should be our utmost goal as a society that we stay technologically literate so that we make our technology supplement our lives and work for us as opposed to being dependent on it to survive.

How much time is too much time?

Smart phones have positive benefits for children when used in small amounts, however there are dangerous consequences if their usage is excessive and left unchecked. For the sake of clarity, “excessive phone usage” will refer to the American Academy of Pediatric’s (AAP) 2018 suggested screen time limits.

“Avoid digital media for toddlers younger than 18 to 24 months other than video chatting. For children 18 to 24 months, watch digital media with them because they learn from watching and talking with you. Limit screen use for preschool children, ages 2 to 5, to just 1 hour a day of high-quality programming” [1].

Cell phones can permanently stunt a child’s neural development

Scientists have identified the first three years of a child’s life to be their “critical years,” a time when their brains are undergoing the most development and are the most sensitive to new information. It is imperative that children constantly interact with their parents via face to face communication, problem solving, and play in order to begin experiencing life while establishing the literal building blocks that will enable them to perceive and interact with the world around them for the rest of their lives. Children’s minds are akin to soft clay that can be easily molded, and both positive and negative experiences can have lasting effects on them. Excessive screen time can cause permanent damage to the brain and can inhibit “the ability to focus, to concentrate, to lend attention, to sense other people’s attitudes and communicate with them, (and) to build a large vocabulary….”

The short term, immediate gratification responses that phones constantly give usually train our brains to become addicted to always expecting quick responses from tasks that we engage in. This can make completing longer tasks that require more focus such as reading, paying attention in class, doing homework, or holding a conversation more difficult and can have lasting ramifications on a child’s performance in school and in social settings [2].

Excessive usage can make children socially awkward and anxious

As most teens and adults learn the hard way, the best way to grow socially is by directly engaging in the social behaviors that we often dread the most. Making new friends, talking to the opposite gender, and public speaking all become easier the more a person partakes in the activity despite how nerve-wracking they may initially be. This is especially true for children, who are socially clean slates that learn how to socialize by interacting with other children, their parents, and through play. Cell phone usage promotes a sedentary lifestyle, and a child can rarely grow socially by being sedentary. Playing with other kids teaches cooperation, empathy, and compassion. These are very human traits that cell phones cannot teach a child. Failing to develop strong social skills can lead to social anxiety, which has a host of its own problems, since a child may be ill-prepared to deal with social scenarios such as these ones.

The AAP recommends interacting with your child by asking them questions and encouraging a response while they use phones instead of just leaving them to their own devices. This way, they are interacting with their parents, as is necessary for their growth, and having the phone supplement their learning in the way that it is supposed to.

Prolonged usage can easily lead to addiction and dependence

Our brains have a built-in reward system that awards us when we achieve something of value. The chemical most commonly associated with this system, and most well-known by society, is dopamine. Normally, our brains receive dopamine in reasonable and completely safe doses as we go about our day whenever we feel we should be rewarded for something. This can include finishing an assignment, sending a difficult email to an even more difficult colleague, or when eating sweets. It makes us feel good and relaxed but can be addicting in large amounts. Cell phones can cause an overproduction of dopamine that has been compared, though to a lesser extent, to the excessive amount of dopamine produced as a result of abusing hard drugs, such as cocaine. Have you ever caught yourself reaching for your phone, without even thinking about it, as soon you hear a text message notification go off? That’s dopamine at work. It’s the rush that we get when something satisfactory happens, and it is all too easy to trigger with phones. Dopamine can easily become addictive, and the brain can become dependent on receiving a certain amount of dopamine every once in a while if it receives too much too quickly. This may be one reason why we may sometimes glance at our phones even if we know there is nothing new to look at.

In children whose brains are still developing, this dependence on dopamine can be catastrophic towards their growth. Their brains are much more susceptible to dopamine addictions than teens or adults are, though this is not to imply that older populations are safe. This is why a child may seem impossibly glued to a phone and will throw a tantrum once they are told to put it down. A proven method to help rid addictions, including cell phone addictions, is to replace the addictive behavior with a similar, healthier, but equally satisfying behavior. Phones can be replaced with Legos, or other interactive toys, in order to teach a child that there are ways to have fun besides phones. Going cold on an addiction rarely works as it does not sate the brain’s hunger for dopamine.

It is entirely possible for us to regain control

Fortunately, there are plenty of solutions that families can utilize in order to make sure that phones do not dominate their lives. Professional organizations such as the AAP and Mayo Clinic stress the importance of unstructured playtime for the minds of young children. In general, psychologists have realized that unstructured play is actually vital for the growth of children’s brains since it encourages creativity, imagination, and problem solving. Their brains are encountering problems, and thus creating solutions that lead to growth and understanding, while they play. Cell phones, on the other hand, tend to do the work for them instead and do not allow the brain to learn. This is especially true for videos that tell children everything that they need to know and do not give them time to problem-solve on their own.

The AAP encourages parents to establish a Family Media Plan that clearly outlines when and where family members can use their technology. Parents may consider forbidding technology at certain places, such as the dinner table, or doing activities, such as weekly board game nights, without technology either in order to remove the barriers that technology so often puts between us. A strong family is one where all family members have firm trust, understanding, and respect in between one another. Less face-to-face interaction, and an obsession with screens from both parents and children, can very much damage these bonds. You can make a Digital Media Plan for your family at www.HealthyChildren.org/MediaUsePlan.

Technology is awesome when used properly and in reasonable amounts!

Virtually every person can name at least one technological medium that brings them joy and can bring them closer to the people that they care about. For some, this may be gathering around the couch and watching a movie or TV show. Others may prefer interactive video games that can bring the family together and can promote bonding in ways similar to board games. The internet also possesses an infinite treasure trove of resources that can greatly enhance education and our general quality of life. This technology mainly becomes problematic once we fail to monitor it properly and allow it to spiral out of control. But in moderation and under control, these innovations are a series of mind-blowing inventions that dazzle the mind and can very much aid our personal and family goals.

There are organizations out there that are constantly raising awareness and promoting online safety

In recent years, parents have realized how destructive cell phones can be to their families and have decided to do something about it. “Wait Until 8^th” is a grassroots movement that encourages parents across the country to take a pledge that they will not give their children a smart device until they are at least 8 years old. It was started by Brooke Shannon and a few other parents in Austin, Texas, and works to empower parents and communities about the dangers of cell phones for kids. You can learn more about the pledge at www.waituntil8th.org.

There is also a wealth of resources for parents that are concerned about their children’s online safety. The National Cyber Security Alliance, Project Safe Childhood, and National Center for Missing and Exploited Children all help spread awareness about internet safety and the consequences of careless internet surfing. It should be a goal of every parent to stay technologically literate and up to date about which websites their children are visiting and the apps that they use.

Make technology work for you, as opposed to working for it

Our world is changing faster than we can adapt to it, and smart phones are no exception. New technology always presents new challenges, especially when it can take so long to thoroughly research the effects that this technology can have on our minds and bodies. It is important to always stay technologically literate so that we may provide the best quality of life that we can for our families. Technology, above all else, is a double-edged sword.

References

1. “Children and Media Tips from the American Academy of Pediatrics.” org, 1 May 2018, www.aap.org/en-us/about-the-aap/aap-press-room/news-features-and-safety-tips/Pages/Children-and-Media-Tips.aspx.
2. “What Screen Time Can Really Do to Kids’ Brains.” Psychology Today, Sussex Publishers, www.psychologytoday.com/us/blog/behind-online-behavior/201604/what-screen-time-can-really-do-kids-brains.

Radiation, which refers to emissions of light or particles, is a type of energy transfer. Radiation takes place at any given moment in the environment or the body. Among sources of radiation to which humans are exposed daily are sun rays, radio waves coming from devices such as mobile phones and TV sets, appliances such as ovens or irons that emit heat, and medical machines such as ultrasounds. The radiation emitted from devices and machines do not cause ionization. Ionizing radiation is made up of high-energy wavelengths or particles, and this is the kind of radiation we get from x-ray, CT, and nuclear imaging. This is used to penetrate tissue to reveal the body’s internal organs and structures. Ionizing radiation can damage DNA, and when our cells cannot fully repair the damage, this may result in DNA mutations.[1] The radiation which poses real danger to humans and has the power to ionize is when radioactive—or unstable—atoms decay and emit alpha (α), beta (β), and gamma (γ) rays.

The earth, air, water, and all living things are more or less radioactive because radioactive atoms are everywhere. The average person is annually exposed to radiation levels of 2.6 – 10 mSv (millisievert), which is not that alarming. The maximum limit recommended for people exposed to radiation for occupational reasons is 100 mSv. The lungs of a person who smokes one pack of cigarettes a day are exposed to an annual radiation of 106 mSv.

How can we protect ourselves?

It is recommended by the World Health Organization that children younger than 16 should not use mobile phones; when they do, their calls should not exceed 10 minutes. When purchasing devices, you should also take into account its SAR (Specific Absorption Rate). Prefer devices with a SAR<1 W/kg. It is also recommended to unplug electrical devices when you are not using them, to keep electrical appliances as far away from your head as possible, use the hairdryer for short periods and in intervals, and to avoid using mobile phones for long conversations (or use headphones!).

It’s also worth reconsidering whether using radiation-emitting devices such as mammography, x-rays, or ultrasounds are absolutely necessary. In 2010, the British Department of Health and Social Care banned using tomography for screening purposes. Another study in the US found that one in ten people are exposed to high levels of radiation because of medical tests.

The average radiation rates (mSv) a person was exposed to during use of certain imaging devices is as follows:

Researchers also found that employees in nuclear power plants were exposed to amounts of radiation that far exceeded allowable amounts.

Beware of radon

The natural radiation humans are exposed to most is the gas radon. Some matter with radioactive atoms such as uranium and thorium – both present in the earth since its birth – emit radon, which seeps through the earth and into the walls of houses and through gaps in plumbing. It is recommended to air houses at least 15 minutes every 24 hours as the only way to be protected from radon.

The resistance of living things

Creatures have been created with different forms of resistance to the elements, including radiation. For example, dogs have a lower resistance than humans, while many other creatures such as rabbits, tortoises, and fruit flies have a higher resistance. And then there is the cockroach, which can survive even a nuclear attack. The lethal radiation dose for cockroaches is an incredible 670- 1000 Sv, whereas it is 6-8 Sv for humans.

Scorpions are also much more radiation-resistant than humans. They can withstand up to 1500 Sv, an amount that is 250 times the maximum dose humans can take. Studies have found a correlation between the strength of a scorpion’s venom and their resistance to radiation. The greater the amount of venom, the greater the resistance they have. The presence of the neural transmitter serotonin supports this view.

Are humans radioactive too?

Humans contain trace amounts of radioactive atoms, namely uranium (²³⁸U), potassium (⁴⁰K), and carbon (¹⁴C). An 80 kg human has natural radiation of 8000 becquerel every second, which is equal to 100Bq per kilogram. This amount is not high enough to cause any worry. The human body has 40 trillion cells on average, and every cell has about 100 trillion atoms. The proportion of the radiating atoms in the body is about 8000/4×10²¹.

Precision protection

The radioactive atoms in the body with the highest probability for carcinogenic effects are potassium (⁴⁰K) and carbon (¹⁴C) atoms. The decomposition that leads to cancer stems from mutations in genes, but the molecules that are the building blocks of genes do not have potassium atoms. The likelihood that a cell gets harmed is very low: it is necessary that the particles emitted from the radioactive potassium atom crash into the DNA molecule and harm it, which is as unlikely as threading a needle when blindfolded. The DNA is precisely protected inside the nucleus located at the center of the cell. If we consider the fact that the average diameter of a cell is about 10 microns (1 micron is one-thousandth of a millimeter), we can better appreciate how little space DNA occupies.

Radiocarbon atoms (¹⁴C), on the other hand, might be present in DNA molecules, and they are more dangerous because the emitted particles are more likely to find the target despite having weaker radioactive properties than potassium. A radioactive carbon atom turns into a nitrogen (¹⁴N) atom and may thus cause a chemical change in the DNA. In other words, the carbon atom is possibly to blame for the unexpected development of cancer.

The likelihood of harmful radioactive particles hitting a person’s DNA is low, and the protective system provided for it lowers the likelihood of developing cancer even more. New DNA molecules that form during DNA coupling are repeatedly checked by inspector enzymes. If there is an error, it is detected and then corrected. The broken code is taken out to be replaced with the correct version. Meanwhile, all these steps are checked by other enzymes assigned to the task. More errors might be made in the newly produced DNA molecule because of external factors. Yet ribosomes in the cell start to produce repair enzymes, as per the instructions from the DNA.

When thinking about all the protective factors that have been coded into the DNA for our survival against the 8000 radioactive activities that occur in our body every second, one cannot help but feel awe for the infinite mercy and wisdom that operate in our lives.

References

• http://time.com/5069317/california-mobile-phone-radiation/
• https://www.health.harvard.edu/cancer/radiation-risk-from-medical-imaging
• Choppin, G. et al., Radiochemistry and Nuclear Chemistry, Oxford: Elsevier Science & Technology, 1995.
• www.physics.isu.edu/radinf/natural.htm

[1] https://www.health.harvard.edu/cancer/radiation-risk-from-medical-imaging

In recent years, people have been divided by conflicting studies about the risk of cancer posed by cell phone radiation. Does the current conflicting research eradicate or support the cell phone-cancer controversy?

Cell phone use has shown a dramatic increase in the world during the 1990s. The heated controversy today is about whether there is a relationship between cell phone use and the risk of developing malignant and benign brain tumors. This controversy did not exist—at least in the eyes of the public—until accumulating anecdotal evidence began suggesting a link between cell phone use and cancer. Since the first pieces of anecdotal evidence, numerous studies have investigated the cell phone-brain cancer link and a general summary of the findings is, at best, confusing. The substantial room for improvement in the experimental designs of these studies, the appearance of brain cancer after a long period of exposure, and some conflicts of interest among researchers prevented the results from being conclusive. More recent studies provide growing evidence for the link, suggesting there is reason to be suspicious about the studies that refute the relationship between cell phone use and brain cancer.

Possible health issues regarding exposure to radio frequency (RF) energy were described in a previous Fountain article (Tombak, 2002). This article also stated that proving or disproving the existence of RF exposure’s biological hazards remains an issue for epidemiology due to relatively low exposure levels, relatively small populations, and a lack of reliable dose estimates. The National Cancer Institute (NCI) is now maintaining an up-to-date web page to inform the public on key points that can be drawn from epidemiological studies investigating the cell phone-brain cancer link. It would be advisable that individuals concerned about this potential link become familiar with this web page and visit frequently to check the updates. A regular visitor will notice that the language on this page is evolving in every update in a way that the most recent version is less likely than the previous one to discredit the link as “out of the question”. This is because we are starting to see—albeit still opposed as weak—stronger signs of the alleged link as there is an increase in both the sheer number and the experimental design quality of relevant studies.

The first two key points that NCI draws on concern the type of electromagnetic energy emitted by cell phones, and the factors that determine a users energy exposure level. It would not be surprising if this train of thought followed with a third key point that stated that the cancer risk depended on the amount of energy that each individual was exposed to. However, the third key point quickly draws the conclusion that “studies thus far have not shown a consistent link between cell phone use and cancers of the brain, nerves, or other tissues of the head and the neck.” It further states “more research is needed because cell phone technology and how people use cell phones have been changing rapidly”.

Regardless of what type of general message one gets from these three key points, I want to emphasize that there is benefit in avoiding a lump-sum conclusion, and in making oneself aware of the results of individual studies. Before I move on to individual studies, however, I will point out how scientifically sound interpretations of statistical power and significance may lead to categorizations as ‘non-existent’ or ‘weak’, but how this scientific reasoning can potentially be misleading for the population at large. In this manner, one would better be able to make sense of why cell phone companies are, on one hand, highlighting the studies that have failed to find a causal link between cell phone use and brain cancer, but on the other hand, are taking all legal precautions necessary to prevent a future litigation by inserting a warning slip in fine print that cautions users not to hold the phone closer than a certain distance against one’s head or body.

The null vs. the alternative

A statistical hypothesis test involves two hypotheses: the null and the alternative hypothesis. The null hypothesis represents the status quo; it assumes that there is no real difference between the two groups under study and the observed difference can be attributed to random chance. Drawing a parallel with legal systems, the presumption that a defendant is innocent until proven guilty can be interpreted as saying that his or her innocence is the null hypothesis. There has to be sufficient evidence on the contrary, i.e showing the guilt, in order to be able to convict the defendant. In a similar fashion, an epidemiological study investigating the presence of a link between cell phone use and brain cancer would have a null hypothesis that states the absence of such a link. The cell phone technology is assumed to be innocent unless the data prove otherwise.

The alternative hypothesis, the latter of the two, represents the claim that there actually is a statistically significant link between cell phone use and brain cancer, and the observed link cannot be attributed to random chance. In our legal analogy, the alternative hypothesis is laying the charges against cell phone technology, thus as the Latin maxim “semper necessitas probandi incumbit ei qui agit” states, the burden of proof lies with the alternative hypothesis.

As a consequence of this construction, a hypothesis test can have only one of two conclusions. If the data shows results that are beyond some predetermined significance level, the null hypothesis is rejected and the researchers believe that there is sufficient evidence to say that the alternative is true. Such a conclusion would establish a link between cell phone use and brain tumors. On the other hand, if the results do not reach the desired significance level, the conclusion is not the confirmation of the null hypothesis, but a failure to conclude that the alternative is true. In other words, when the desired significance level is not reached, the only outcome is a lack of conclusion; the test would not falsify the null hypothesis but would not declare it to be true either. The accused would be vindicated on the basis of insufficient evidence.

News on the innocence of cell phone technology, or any technology for that matter, should be read primarily with this perspective in mind. The conclusions of research studies are reported on the basis of whether the results “reach or fail to reach significance”. However, a more meaningful statistic to report from the study would be the deviation of the results from significance, if they were not significant. Results that are close to statistical significance can still be “meaningful”. After all, the significance level chosen for most studies relies more on traditional scientific habits than anything else. In this perspective, it can even be called arbitrary. In reality, we may not have expertise in today’s world to determine whether a 5% significance level is more meaningful than a 10% when it comes to studying the link between cell phone use and brain cancer. So when the NCI officials mention “lack of a consistent link,” all of what they mean is that the desired significance level has not been reached in most credible and up-to-date studies. Yet, the public is not informed about how significant the results were. Furthermore, as we see in the much-acclaimed Interphone study, failure to reach significance in the entire study may be overshadowing the fact that significance was attained for a subgroup of people, for instance, the top 10% of the population with highest cell phone use (The Interphone study group, 2010).

Perspectives on brain cancer risk

News regarding cell phone tumor risks is plainly confusing because a battle continues among different international panels and interest groups over how to analyze and interpret cell phone tumor data. An article (July 6, 2011) on Microwave News explains why there is no overlap in the conclusions made by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) and the International Agency for Research on Cancer (IARC), the two panels that are supposed to work together, but fell into deep disagreement as the data started showing some link between cell phone use and brain cancer. This piece is a highly suggested read for anyone who would like to be able to make more sense of the past and potentially future news on cell phone tumor risks.

The Interphone study

Much of the current debate on cell phone tumor risks actually revolve around the Interphone study, which was conducted by a consortium of researchers from 13 countries, and is the largest health related case control study of the use of cell phones and head and neck tumors. According to NCI’s summary, “most published analyses from this study have shown no statistically significant increases in brain or central nervous system cancers related to higher amounts of cell phone use. One recent analysis showed a statistically significant, albeit modest, increase in the risk of glioma among the small proportion of study participants who spent the most total time on cell phone calls. However, the researchers considered this finding inconclusive because they felt that the amount of use reported by some respondents was unlikely and because the participants who reported lower levels of use appeared to have a reduced risk of brain cancer.”¹

The general message that comes across in NCI’s summary of Interphone results is that we do not have enough reason to believe that cell phones are dangerous. However, it is very important to remember that one can never accept the null hypothesis that “cell phones are safe.” The only conclusion that can be drawn is on the basis of insufficient evidence, which is to say that cell phones are dangerous since the desired significance level has not been reached.

As the Interphone study is the largest of its kind, it has drawn substantial attention from concerned parties, and a significant part of this attention has been in the form of harsh criticisms for the experimental design, data analysis, and stated conclusions. For instance, one of Interphone’s biggest critics, the International Electromagnetic Field (EMF) Collaborative, published a paper in May 2010 detailing the flaws of the study. Among other things, these flaws included using data from 2004 and before when cell phone use was much less common, categorizing subjects who used cordless phones (which emit the same microwave radiation as cell phones,) as ‘unexposed’; exclusion of many types of brain tumors; exclusion of people who had died, or were too ill to be interviewed, as a consequence of their brain tumor; and exclusion of children and young adults who are more vulnerable.

In August 2009, more than forty leading independent scientists, physicians and other experts from fourteen countries endorsed the white paper “Cell-phones and Brain Tumors: 15 Reasons for Concern, Science, Spin and the Truth Behind Interphone” by US researcher Lloyd Morgan. Investigating the research on cell phone tumor risks including the Interphone study, this paper concluded that “there is a risk of brain tumors from cell phone use; telecom funded studies underestimate the risk of brain tumors; and children have larger risks than adults for brain tumors”. Unlike the Interphone study, some industry funded research also accepts the risks associated with cell phone use. In 1999, Dr. George Carlo, head of a $25m research body funded by the mobile phone industry in the US, said his study showed an increased risk of getting a type of rare brain tumor from using mobile phones. This early in the debate, he was probably one of the first researchers with links to industry who stopped ruling out the tumor risks of cell phones.

A review of other main studies

Hardell et al.

Dr. Lennart Hardell, from Örebro University in Sweden, is one of the most adamant leaders in cautioning the world about cell phone tumor risks. In 2007, he and his team reported that cell phone users were at an increased risk of malignant glioma, and that a daily one-hour exposure significantly increased the risk for developing a brain tumor after 10 years (Hardell et al., 2007). In a more recent study also cited by NCI, they found statistically significant trends of increasing brain cancer risk for the total amount of cell phone use and the years of use among people who began using cell phones before the age of 20 (Hardell et al., 2011). They also published a number of other papers in epidemiological journals pointing to the risks associated with cell phone and cordless phone usage.

The Danish cohort study

A 2011 cohort study in Denmark linked billing information from more than 420,000 cell phone subscribers with brain tumor incidence data from the Danish Cancer Registry (Frei et al., 2011). This study was an update on the 2006-update of a 2001 cohort study (Schüz et al., 2006; Johansen et al., 2001) that has been dogged by controversy and political suspicions since the first results were published ten years ago. NCI cites the study and states that the analyses found no association between cell phone use and the incidence of glioma, meningioma, or acoustic neuroma, even among people who had been cell phone subscribers for 10 or more years. However, there is no mention of the published or vocal criticisms of the study.

The main criticism for the study is that more than 200,000 corporate mobile subscribers were excluded from the cohort as cell phone bills were not in users’ names. Microwave News states, “In the time period covered in the Danish project—from 1987 through 1995—cell phones were expensive and it’s no stretch to assume that those who did not have to pay their own bills racked up the most talk time.”² Thus, the study designers effectively removed one-third of the population with the heaviest cell phone use. Dr. Lennart Hardell had also criticized the original 2001 paper by publishing on the shortcomings that make the conclusions premature (Hardell and Mild, 2001). Concerning the 2011 update, the Microwave News bluntly suggests, “Don’t believe a word of it”.

It is also interesting to note that the results came just five months after a panel of experts from the World Health Organization’s International Agency for Research on Cancer (IARC) deemed cell phones a possible cause of cancer—a statement that sparked fear in many of the world’s 5 billion cell phone users.

Conclusion

While there is still no established causal link between cell phone use and cancer, we know as a fact that different research groups have found an increased risk of a rare type of brain cancer among heavy users. Even though children are known to be at a greater risk because of being in earlier stages of neural development, it is unfortunate that data from children were not included in studies until very recently. Concerned citizens of the world need to raise awareness about the behind-the-scenes battle taking place between different international panels and interest groups. This will make a reliable interpretation of conflicting news more possible. Further corroboration for both statistical and anecdotal evidence on the relationship between cell phone use and brain cancer may be necessary to “prove” a link, but this should, by no means, be interpreted as a vindication of cell phones. In the meantime, it is only safe to take precautions oneself, and encourage loved ones to reduce exposure to electromagnetic energy from cell phones by using a hands-free device and by reserving the use of cell phones for shorter conversations.

Notes

1 http://www.cancer.gov/cancertopics/factsheet/Risk/cellphones

2 http://www.microwavenews.com/DanishCohort.html#Continued

References

• Frei P, Poulsen AH, Johansen C, et al. 2011. “Use of mobile phones and risk of brain tumours: update of Danish cohort study.” British Medical Journal; DOI: 10.1136/bmj.d6387.
• Hardell, L., Walker, M. J., Walhjalt, B., Friedman, L. S. and Richter, E. D. 2007. “Secret ties to industry and conflicting interests in cancer research.” American Journal of Industrial Medicine,; 50: 227–233. doi: 10.1002/ajim.20357.
• Hardell L, Carlberg M, Soderqvist F, Hansson-Mild K, Morgan LL. 2007. “Long-term use of cellular phones and brain tumours: Increased risk associated with use for > or = 10 years.” Occup Environ Med. 64:626–632.
• Hardell L, Carlberg M, Hansson Mild K. 2011. “Pooled analysis of case-control studies on malignant brain tumours and the use of mobile and cordless phones including living and deceased subjects.” International Journal of Oncology; 38(5):1465–1474.
• Hardell L, Mild KH. 2001. “Re: Cellular Telephones and Cancer—a Nationwide Cohort Study in Denmark”; JNCI J Natl Cancer Inst. 93(12): 952.
• Johansen C, Boice Jr. JD, McLaughlin JK, Olsen JH. 2001. “Cellular telephones and cancer: a nationwide cohort study in Denmark.” Journal of the National Cancer Institute; 93(3):203–207.
• Schüz J, Jacobsen R, Olsen JH, et al. 2006. “Cellular telephone use and cancer risk: update of a nationwide Danish cohort.” Journal of the National Cancer Institute; 98(23):1707–1713.
• Tombak, Ali. 2002. “Biological Effects of Cellular Phones.” The Fountain, 37 (1).
• The Interphone Study Group. 2010. “Brain tumour risk in relation to mobile telephone use: results of the Interphone international case-control study.” International Journal of Epidemiology; 39(3):675–694.

In today’s cellular communication systems, cellular phones operate in several frequency bands. European systems use the Global System for Mobile Communications (GSM) at around 900 MHz and 1800 MHz; American systems use 850 MHz and 1900 MHz, frequencies that fall between the operating frequency ranges of televisions and microwaves. This frequency range is called non-ionizing, for the wave’s energy does not release electrons from atoms in living tissue. For instance, an X-ray is an ionizing wave that, to a degree, damages exposed biological material. Therefore, most concerns deal with RF energy’s heating effect rather than with ionization.

Technical Motivation

The electromagnetic spectrum extends from DC (direct current) to ionizing radiation. Scientists divide this spectrum into subregions. Cellular phones fall into the ultra-high frequency (UHF) regime, specifically from 300 MHz to 3000 MHz. By itself, a continuous UHF wave carries no information and does not enhance communication. It only becomes useful when modulation, defined as means carrying the information on a high frequency carrier, like UHF, is applied. The most common modulation techniques are amplitude modulation (AM) and frequency modulation (FM).

The capacity of the spectrum’s given section to carry information is limited by the Shannon Theorem. According to this theorem, channel capacity can be increased by increasing the system’s signal-to-noise ratio. In wired communications, channel capacity can be increased by adding more parallel optical fibers. Channel capacity in wireless communications can be increased by transmitting weak signals that attenuate rapidly near the transmitter and thus provide a given portion of the electromagnetic spectrum to be utilized many times. How a given spectrum is allocated among users affects the channel capacity. Therefore, there are several coding techniques, the most common of which are Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA).

Neglecting some small details, an electromagnetic (EM) wave’s energy is expressed in terms of power density (W/m2) across a surface. Power density measures an incident EM wave’s strength. Easily measured, it is a very preferable metric to UHF fields. For uncontrolled environments, the American National Standards Institute and the Institute of Electrical and Electronics Engineers (ANSI/IEEE C95.1) recommend a 2 to 20 W/m2 for an average external exposure to UHF. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has similar power density recommendations for limiting the general public’s exposure to RF energy so that people will not be overheated by RF energy. As a comparison, for example, summer sunshine peaks around 1000 W/m2.

However, as power density is not a good indicator inside a living organism, scientists have defined a Specific Absorption Rate: SAR (in W/kg). For uncontrolled environments, ANSI/IEEE limits the spatial-average SAR to 0.08 W/kg whole body and to 1.6 W/kg averaged over any 1 gram of tissue. Also, 1998 ICNIRP restrictions are similar to ANSI/IEEE’s. The SAR can be estimated in three ways.

– Micro-antenna: Small antennas can determine a tissue’s electric field as well as its SAR. But it is difficult to place the antenna, and the tissue’s properties may not be known.

– Miniature thermal probes: Since RF energy heats the tissue, this technique detects the heat and the SAR in the neighborhood of the temperature cell, which then can be computed accordingly. However, this method also seems very difficult technologically.

– Numerical modeling: The numerical modeling of macroscopic bodies enables a numerical simulation, known as the Finite Difference Time Domain (FDTD), that can estimate the SAR. However, this process can be time-consuming and expensive.

Possible Health Issues

An EM wave can effect a biological change in living tissue in two ways: Depositing enough energy while passing through the biological material to alter some structures, or depositing packets of energy larger than the bond energy. Yet neither way seems to be possible, for the photon energy within the UHF zone is far less than the bond energy or the energy required to alter a living tissue’s structures. Therefore, many scientists now argue that UHF radiation at subthermal power levels can cause some biological damage.

Due to relatively low exposure levels, relatively small populations, and a lack of reliable dose estimates, proving or disproving the existence of RF exposure’s biological hazards remains an issue for epidemiology (e.g., statistical analysis of health records and animal studies).

Epidemiological Studies

Epidemiological studies were conducted among people who worked in a high frequency environment, such as radar stations. Search criteria were not limited to cellular and personnel communication system (PCS) frequencies. Due to the nature of radar and other military equipment, broader frequency ranges were covered. The epidemiology of cancer and RF radiation includes studies of cancer mortality rates among those exposed to RF energy.

Throughout these studies, people’s records were searched to determine if their cancer was due to RF exposure. These studies were made in various institutions, including the Radar Laboratory of the Massachusetts Institute of Technology, the U.S. Navy and Air Force, and the Polish military. There was no conclusive evidence that RF exposure increases the risk of cancer. Also, due to the lack of comparisons with total cancer, it was suggested that RF exposure does not have a strong effect on cancer.

Since brain cancer takes a long time to develop and epidemiological studies tell nothing about future risks, these studies have not proved or disproved that RF exposure increases the risk of cancer.

Animal Studies

Animals are the other source of information that potentially may answer people’s concerns. Experiments have studied rats exposed to certain power levels of RF energy. However, these studies found no link between cell phones and cancer.

In 1999, a Motorola-funded research program concluded that exposing rats to pulse-modulated 837 MHz RF energy, very close to that radiated by a digital cell phone, does not cause or develop brain cancer. A study in April 2000 reported that this conclusion is valid for continuous-wave RF (analog cell phones). But a 1995 study at the University of Washington (Seattle) reported that exposing rats to RF radiation at an average whole-body exposure of 1 W/kg of body weight caused breaks in their brain cells’ DNA, which is an indication of cancer. No other study has confirmed this finding.

Other studies have focused on different aspects of RF radiation rather than brain cancer. They searched animals for certain diseases and noticed an increase in disease rate. However, despite such research findings, animal studies seem to be far removed from human health.

Conclusion

Epidemiological findings and animal studies have neither proved nor disproved the health hazards of mobile phones. A February 2000 essay by the U.S. Food and Drug Administration (FDA) stated that: There is currently insufficient scientific basis for concluding either that wireless communication technologies are safe or that they pose a health risk to millions of users. Research activity continues. For example, France’s International Agency for Research on Cancer has received a research project of 8 million euros from the European Commission for a 3-year, wide epidemiological study. Also, the FDA and the Cellular Telephone Industry Association have undertaken a $1 million research project to clarify the health risks of mobile phones.

Meanwhile, some researchers are trying to find the head’s SAR by using electromagnetic simulations (FDTD). So far, they have discovered that it is strongly affected by the cell phone’s position as well as the head’s shape and properties. Therefore phone-makers are trying to design handset designs to reduce the SAR. However, it seems that the debate will remain until scientific proof is confirmed and made available.

• References
• http://www.fda.gov/cdrh/ocd/mobilphone.html.
• IEEE Spectrum. Are Mobile Phones Safe? (August 2000): 23-28.
• Moulder et. al. Cell Phones and Cancer: What is the Evidence for a Connection? Radiation Research Society, 151 (1999): 513-31.