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EHHI-Cell Phones--Technology, Exposures, Health Effects

Health Risks of Cell Phones

  • Russian and Eastern European scientists issued the earliest reports that low-level exposure to RF radiation could cause a wide range of health effects, including behavioral changes, effects on the immunological system, reproductive effects, changes in hormone levels, headaches, irritability, fatigue, and cardiovascular effects.
  • Since the first reports appeared in the literature, scientists have recognized the near-ubiquitous use and exposure to cell phones and other radiofrequency technologies in the last decade, and have launched and completed many studies. As the science has matured, researchers and government officials have become increasingly concerned about exposures that affect pregnant women—and their fetuses . Their concern is also for children whose brains and organs do not fully mature until age 21.
  • Non-ionizing radiation, with long wavelength and low frequency, does not break chemical bonds, but has sufficient energy to move electrons and heat body tissue, leading to biological effects at certain doses. Except for optical radiation, there is little data on the quantitative relationships between exposures to different types of non-ionizing radiation and effects on human health.
  • In 1996, theWorld Health Organization (WHO) established the International EMF Project to review the scientific literature concerning biological effects of EMFs, and will conduct a formal risk assessment of all studied health outcomes from exposure to RF fields by 2012.
  • The majority of studies examining biological and health effects of cell phone radiation have focused on the potential of cell technologies to cause cancer, nervous system disorders, and adverse reproductive effects.

Cancer

  • Since RF-EMFs are emitted from cell phones in close proximity to the head, the potential for brain tumors has been a concern. Most studies have focused on potential associations between cell phone use and only a few types of brain tumors.
  • Several studies have found an increase in the risk of developing some types of tumors after long-term exposure, but experimental studies are not available to explain the link, causing some to remain skeptical about the association. Overall, 33 peer-reviewed epidemiologic studies on cell phones and cancer have been conducted. Twenty-five of these studies have focused on brain tumors.22 Some have found a risk of cancer with long-term use of cell phones,23 while others have not.24
  • Data derived from studies spanning decades may be dated by the time they are published, due to rapidly changing technology and cell phone use patterns. A National Cancer Institute (NCI) case-control study of brain tumors and use of cell phones by adults which began in 1994—11 years after the first commercial cell phone was activated in the United States—found no indication of higher brain tumor risk among people who had used cell phones compared with those who had not used them. However, patterns of cell phone use and the types of phones used in the United States have changed since the early to mid-1990s, and few users in the study reported using cell phones for five years or more.25
  • Strong studies about the relationships between cell phone use and cancer have been published by Hardell et al. andWHO’s International Agency for Research on Cancer (IARC). Both Hardell et al.and IARC’s Interphone studies are the subject of criticism about methodological deficiencies, inadequate exposure assessment, and problems with recall and response.
    • IARC’s Interphone study, the largest cell phone health study conducted, found “suggestions of an increased risk of glioma at the highest exposure levels” but notes “biases and error prevent a causal interpretation.”26 The Mobile Manufacturers forum notes that it provides assurance of the safety of cell phones, and the Food and Drug Administration (FDA) notes that these biases and errors limit the strength of conclusions that can be drawn from it. Others argue that the study may underestimate the real risk of cell phones today, noting that the average present-day user in the U.S. could fall into this “highest level of exposure” risk use category after about 13 years.27
    • The Swedish researcher Dr. Lennart Hardell et al. have conducted six independently funded studies on cell phones and tumors, using the Swedish Cancer Registry, and has found a consistent pattern of increased risk for glioma and acoustic neuroma after 10 years of mobile phone use. Noting that the evidence for risks from prolonged cell phone and cordless phone use is “quite strong,” Hardell et al. concluded, “For people who have used these devices for 10 years or longer, and when they are used mainly on one side of the head, the risk of malignant brain tumor is doubled for adults and is even higher for persons with first use before the age of 20 years.”28
  • Critics of Hardell’s studies claim “recall bias” prevent objective data, and have prevented Hardell’s work from supporting a theory of cancer causation in humans in legal decisions. The Daubert standard rule of evidence requires scientific evidence to be “reliable and relevant” in order to be admitted to federal court. Others argue that Hardell may have underestimated the risk from mobile phone use and that his research is less biased than that of the Interphone study.29
  • Data from ionizing radiation studies indicate a brain tumor latency time of between 20 and 55 years. Acoustic neuromas associated with childhood radiation exposure used to treat “enlarged” tonsils and adenoids appeared up to 55 years after the original exposure, with a mean of 38 years.30
  • Review studies note that insufficient time has passed to evaluate longterm risks associated with slow-growing brain tumors, but some studies already show possible evidence of an increased risk of brain tumors from the use of cell phones. Almost all research on mobile phone radiation studying an exposure duration of 10 years or longer point towards the existence of an increased tumor risk in the head.31
  • The most recent U.S. brain cancer incidence rates indicate that rates have declined slightly or remained the same, except in those aged 20 to 29. Females in this group experienced a statistically significant increase in frontal lobe cancers, but not in parts of the brain that would be more highly exposed to RF radiation from cell phones.32
  • In 2011,WHO’s International Agency for Research on Cancer (IARC) classified electromagnetic fields as possibly carcinogenic to humans, citing an increased risk of glioma associated with wireless phone use.33 The evidence linking wireless phone use to glioma and acoustic neuroma is considered “limited” and inadequate to draw conclusions for other types of cancers. “Limited evidence of carcinogenicity” is defined by IARC as, “a positive association. . . between exposure to the agent and cancer for which a causal interpretation is considered by theWorking Group to be credible, but chance, bias or confounding could not be ruled out with reasonable confidence.”42
  • The primary goal of IARC is to identify causes of cancer and it has established the most widely used system for classifying carcinogens. IARC has evaluated the cancer-causing potential of more than 900 likely candidates, placing them into one of the groups in Table 3.
  • NCI’s 2011 Annual Report to the Nation on the Status of Cancer notes that the association between long-term (>10 years) cell phone use and brain cancer is unclear, “primarily because of the relatively recent adoption of widespread use of cellular phones, as well as issues of bias and study design.”43
  • The NCI further acknowledges that “acoustic neuromas are of particular interest with regard to cellular phone use because of the proximity of these tumors to the phone” and that the “relatively large number of acoustic neuromas identified in the first four years of data collection suggests that etiologic studies will be possible in the future.”44

Nervous System

  • The effects of exposure to RF-EMFs from cell phones on the human nervous system have been the subject of a large number of studies in recent years. Minor effects on brain activity have been found. but have not been related to adverse health effects. No consistent significant effects on cognitive performance and memory have been observed.45
  • Experiments by Narayanan et al. found that memory retention and retrieval were significantly affected in mobile phone RFEMR- exposed rats.46 Several other studies have also measured cognitive effects in animals (Table 4).
  • Examples of effects in humans include impaired cognitive performance after exposure to a pulsed electromagnetic field47 and slower response times to spatial working memory tasks when exposed to RF from a standard GSM cellular phone placed next to the head of male subjects.48
  • Most studies have focused on changes in cognitive performance after short-term RF-EMF exposure, and most have involved young and middle-aged male and female subjects. Since children represent a sensitive subgroup, as their brains are not yet completely mature, they may react differently to RF-EMF exposure.49
  • A 2011 review of the literature on the effects of RF-EMF exposure on cognitive performance measured in humans found inconsistent study results due to differences in methodology, sample size, composition of study groups, experimental design and exposure setup, as well as the exposure conditions. The authors note, “The lack of a validated tool, which reliably assesses changes in cognitive performance caused by RF-EMF exposure, may contribute to the current inconsistencies in outcomes.” 50
  • The effects of RF-EMF exposure from cell phones on central nervous system (CNS) disorders, such as Alzheimer’s disease, migraine, or vertigo, has been the focus of recent epidemiological research in Denmark, which is the first country to investigate a possible association between the use of cell phones and the risk of CNS disorders.
  • The study found a weak, but statistically significant, association between cell phone use and migraine and vertigo. The Danish study recommended more research in this area, along with RF exposurereducing measures, until more data have been obtained.51

Reproduction

  • Several research studies have examined the effects of RF-EMF on the male reproductive system. The focus of research has included effects on semen quality and potential changes associated with RFEMF exposures and electromagnetic radiation.
  • The potential effects of RF-EMF from cell phones on fertility were investigated in a 2005 epidemiological study, which found correlations between cell phone use and changes in semen quality. 58 An experimental study that same year involving exposure of male mice to RF-EMR noted a significant genotoxic effect on epididymal sperm.59
  • Other studies have correlated the duration of exposure to cell phones with defects in sperm count, motility, viability, and normal morphology, but most of the studies have been small and the evidence remains equivocal.60
  • Agarwal et al. found that cell phone use decreased semen quality in 361 men by reducing sperm count, motility, viability, and normal morphology, and that the decrease in sperm parameters was dependent on the duration of daily exposure to cell phones and independent of the initial semen quality. The same research group placed men’s semen samples 2.5 centimeters (about an inch) away from a cell phone, in talk mode, for one hour. This is an average distance between the testes and the pants’ pocket.
  • Semen exposed to RF electromagnetic waves emitted from cell phones had higher levels of damaging free radicals, lower sperm motility (the ability of sperm to move and swim), lower sperm viability (the percentage of live sperm), and possibly greater oxidative stress.61
  • Several research studies have examined the effects of RF-EMF on the male reproductive system. The focus of research has included effects on semen quality and potential changes associated with RFEMF exposures and electromagnetic radiation.
  • The potential effects of RF-EMF from cell phones on fertility were investigated in a 2005 epidemiological study, which found correlations between cell phone use and changes in semen quality. 58 An experimental study that same year involving exposure of male mice to RF-EMR noted a significant genotoxic effect on epididymal sperm.59
  • Other studies have correlated the duration of exposure to cell phones with defects in sperm count, motility, viability, and normal morphology, but most of the studies have been small and the evidence remains equivocal.60
  • Agarwal et al. found that cell phone use decreased semen quality in 361 men by reducing sperm count, motility, viability, and normal morphology, and that the decrease in sperm parameters was dependent on the duration of daily exposure to cell phones and independent of the initial semen quality. The same research group placed men’s semen samples 2.5 centimeters (about an inch) away from a cell phone, in talk mode, for one hour. This is an average distance between the testes and the pants’ pocket.
  • Semen exposed to RF electromagnetic waves emitted from cell phones had higher levels of damaging free radicals, lower sperm motility (the ability of sperm to move and swim), lower sperm viability (the percentage of live sperm), and possibly greater oxidative stress.61

Other Effects

Genotoxic Effects/Cell Damage

  • Researchers have studied the potential of RF-EMFs to cause changes in a cell’s genetic material (DNA) and/or to damage the genome. “Genotoxic” substances can potentially cause genetic mutations or cellular damage that can contribute to the development of cancerous tumors.
  • The European Union’s in vitro REFLEX study of human cells exposed to cell phone microwave radiation (2000 to 2004) showed that radiation from cell phones has the potential to damage the genome of isolated human cells, but the findings were very controversial. The lead author of the study argues that there is enough evidence that RF radiation can alter the genetic material of exposed cells.72 Other scientists agree: A recent review of 101 papers on the genotoxic effects of RF-EMF found that 49 reported a genotoxic effect.73
  • Numerous studies in laboratory animals have demonstrated that mobile phones or simulated RF radiation exposures can damage cells.While some authors have suggested that this could lead to neurological damage, other authors have not.74 There is no standard testing methodology for the evaluation of possible genotoxic effects of EMFs, which may in part explain why the findings are inconsistent.
  • DNA studies have particular importance with respect to children. Researchers who placed a mobile phone at a one-meter (about a yard) distance from human cells found a reduction in DNA repair in cells with double-strand DNA damage. The strongest effects were observed in stem cells. Since stem cells are more active in children, researchers argue that children may be at an increased risk of cancer from cell phone exposures.75
  • For several decades, Swedish neuroscientists have studied the effects of RF-EMFs on nerve cells. They attached cell phones to the sides of young rats’ cages to create intermittent exposures similar to human usages, and discovered neuron damage in the brains of young rats 50 days after weekly two-hour exposure.76

Ocular Effects

  • Thermal effects from microwave radiation have been reported to cause cataracts and effects on the retina, cornea and other ocular systems, but non-thermal effects are less well understood.77 Studies of non-thermal effects of RF-EMFs from mobile phones are relatively recent. Researchers have recommended further study of effects on the eye lens and lens epithelial cells.78
  • Electromagnetic fields from microwave radiation have been shown to have a negative impact on the eye lens. One study warns, “Highfrequency microwave electromagnetic radiation from mobile phones and other modern devices has the potential to damage eye tissues, but its effect on the lens epithelium is unknown at present.”79

Psychological Effects

  • The addictive nature of cell phones has concerned psychologists for years. Recently, psychologists have warned that smartphone users are especially at risk for becoming addicted to their devices. In a recent study, subjects checked their phones 34 times a day. People may check their phones out of habit or compulsion, but habitually checking can be a way to avoid interacting with people.80
  • Some people can experience withdrawal symptoms typically associated with substance abuse, such as anxiety, insomnia, and depression, when they are without their smartphones. Most of the studies conducted on the potential psychological effects of cell phones have focused on young adults and adolescents.
  • According to a recent Columbia University study, “communication, responsibility, and relationships all seem to be negatively influenced by the use of text messaging” in both early and late adolescent groups.81 Frequent mobile phone use has been associated with stress, sleep disturbances, and symptoms of depression among young adult men and women.82 Yen et al. cite “withdrawal symptoms without cellular phone use” as a common psychological reaction in adolescents to the removal of cell phone access.83

Electromagnetic Hypersensitivity

  • Some individuals experience adverse medical symptoms from exposure to electromagnetic fields. People with electromagnetic hypersensitivity (EHS) report symptoms from even low levels of exposure to non-ionizing electromagnetic radiation.
  • Concerns that cell phones may be associated with EHS are largely a result of complaints from cell phone users about headaches, nausea, dizziness, blurred vision, and other symptoms. Few studies have been conducted on electromagnetic hypersensitivity from exposure to mobile phones.84

Studies Specific to Children

  • Children may be potentially susceptible to RF effects because of their developing nervous systems, increased levels of cell division, undeveloped immune systems, thinner skulls, and more conductive brain tissue. Children experience greater RF penetration relative to head size, and longer lifetime exposure in comparison with adults.85
  • Epidemiological studies demonstrating health effects of RF radiation from cell phones on children are extremely limited. The few studies that have specifically focused on cell phones and children have focused on cancer, behavior, and neonatal heart rate.
  • Cancer, Hardell study
    At the first international conference on mobile phones and health in 2008, Lennart Hardell, M.D., Ph.D., reported that people who started mobile phone use before the age of 20 had a more than fivefold increase in glioma. Those who started using mobile phones when they were young were also five times more likely to develop acoustic neuromas.86
  • Cancer, CEFALO study
    The CEFALO is an international, multicenter, case-control study of the association between mobile phone use and brain tumor risk in children aged 7 to 19.
    • Published in July 2011, the CEFALO study was conducted in Denmark, Sweden, Norway, and Switzerland. It included children and adolescents aged 7–19 years who were diagnosed with a brain tumor between 2004 and 2008.
    • The study found that children and adolescent patients with brain tumors were not statistically significantly more likely to have been regular cell phone users than control subjects. The authors note that the possibility that cell phones might confer a small increase in risk cannot be ruled out and emphasize “the importance of future studies with objective exposure assessment or the use of prospectively collected exposure data.” 87
    • The report has some shortcomings; most notably, it can take 10 years or more to develop cancer following exposure, but only seven years have passed since the beginning of the study.
    • Second, phone use patterns have changed significantly since the study was conducted. In the study, one call per week counted as “regular” use, skewing the results.
    • An analysis of a subset of the data corresponding only to heavy cell phone users, however, found different results. In the author’s words: “[There] was a highly significant association between the time since first subscription and brain tumor risk. Children who used cell phones for at least 2.8 years were more than twice as likely to have a brain tumor than those who never regularly used cell phones.”88
  • Behavior
    Professor Leeka Kheifets, M.A., Ph.D., of the Department of Epidemiology at the University of California, Los Angeles, and her colleagues conducted several studies on children’s exposure to mobile phones early in life and the association with behavioral problems.
  • One study, involving 13,000 children who reached age seven by 2006, concluded that exposure to mobile phones prenatally and postnatally was associated with behavioral difficulties.89
  • More recently, a dataset consisting of nearly 29,000 children who reached age seven by 2008 replicated the previous study, demonstrating that mobile phone use was associated with behavioral problems in children.90
  • Environment and Human Health, Inc.’s forthcoming animal research study shows a relationship between cell phone use in pregnancy and behavioral issues in the offspring.
  • Heart Rate
    Pregnant women exposed to EMF emitted by mobile phones on telephone-dialing mode for 10 minutes a day during pregnancy and after birth had babies with statistically significant increases in fetal and neonatal heart rate. The study involved 90 women with uncomplicated pregnancies. The authors suggest that this may result from a physiological response to the pulsed magnetic fields, and recommend avoidance of cellular phone use during early weeks of gestation, and also recommend further studies. 91
  • Several other epidemiological studies on children are ongoing, but results of these studies are not yet available.

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