The increasing use of mobile phones has resulted in increased human exposure to radiofrequency electromagnetic fields: already more than 80% of the Finnish population have a mobile phone. Although the electromagnetic fields from mobile phones are weak, the high number of exposed persons, together with some provocative but inconclusive scientific results, has raised concerns about possible health hazards. Finnish universities and research institutes have investigated possible health effects of mobile phones in a national research programme. The results of this programme will be reported in a seminar held in Helsinki on 17 October, 2003.
The national research programme was carried out in two parts during the years 1998-2003, and was coordinated by the University of Kuopio (Prof. Jukka Juutilainen). The other participantes were STUK – the Radiation and Nuclear Safety Authority, Technical University of Tampere, University of Turku, Finnish Institute of Occupational Health and VTT Information Technology. The main source of funding was TEKES (National Technology Agency; a governmental organisation). The programme was also supported by Nokia, Benefon, Sonera, Elisa, Radiolinja, Finnish 2G, Mobile Manufacturers Forum and GSM Association.
The first part, ”Electromagnetic Fields from Mobile Phones as a Possible Health Risk” was conducted in 1998-2000. This first part of the programme included 6 research projects:
Project 1: STUK designed, constructed and tested two waveguide exposure chambers for cell culture experiments and designed an exposure chamber for animals. The equipment developed in the project have been used for biological experiments by the STUK and the University of Kuopio in the National Research Programme and in EU-funded research projects.
Project 2: The University of Kuopio studied the possibility that radiofrequency electromagnetic fields enhance cancer development. Skin tumors induced by UV radiation were used as the experimental model. Small differences were observed between the experimental groups, but the study did not show statistically significant effects on tumor development.
Project 3: STUK and University of Kuopio carried out experiments with cell cultures – the project tested different cell lines and methods to identify suitable models for investigating biological effects of electromagnetic fields. According to the results, relatively weak electromagnetic fields may cause cellular changes that are consistent with a stress response.
Project 4: The Finnish Institute of Occupational Health conducted a feasibility study for evaluating the association of cellullar phone use with brain and salivary gland cancers. About 400 brain tumors and 34 salivary gland cancers were identified from the Finnish Cancer Registry. Both case-control and cohort designs were studied but neither of the study designs could be regarded feasible enough at the time of the study, since the percentage of phone users was low.
Project 5: The Finnish Institute of Occupational Health studied possible symptoms caused by mobile phone RF fields on hypersensitive persons. 20 volunteers participated, and both analogue (NMT, 900 MHz) and digital phones (GSM 900 and 1800 MHz) were used as exposure sources. Variety of subjective symptoms or sensations were experienced by the test persons but the symptoms and sensations were not related to the exposure condition (true or sham exposure). None of the test persons could distinguish correctly RF exposure from sham exposure.
Project 6: VTT simulated by using dosimetric computer models the exposure of laboratory animals and cell cultures in the chambers developed in Project No. 1. The objective of dosimetry is to find out the "dose" (i.e. the power absorbed from the electromagnetic field) in cells and laboratory animals. This information is essential in order to proportion the results to exposure of a human using a mobile phone. Also the modelling method itself was studied.
The second part, “Health Risk Assessment of Wireless Communication” was carried out during the years 2000-2003. The second part of the programme included ten projects:
1. The effects of radiofrequency electromagnetic fields on cognition and brain function
2. Human circulatory responses during exposure to radiofrequency wireless communication
3. Effects of cellular phones on cardiac pacemakers
4. Activity of the enzyme ODC in cell cultures following RF exposures at 835 and 900 MHz
5. Budding yeast (Saccharomyces cerevisiae) as a model organism for studying the biological
effects of radiofrequency fields
6. Development of in vitro dosimetry and biomarkers to study in vivo RF-EMF biological effects
7. Dynamic adaptive modelling of the human body for radiofrequency radiation absorption
8. Numerical simulation of RF exposure conditions by the FDTD method
9. Case-control study of brain tumor etiology
10. Possible health effects of electromagnetic fields from mobile phones on hearing and balance
The following results (among other things) were obtained in these 10 projects:
· Centre for Cognitive Neuroscience (CCN, University of Turku) examined the effects of mobile phone on brain electrical activity (EEG), short-term memory and attention (cognitive functions), brain blood flow and metabolism, and subjective symptoms both in adults and children (10-14 years). According to EEG studies (3 studies) mobile phone appears to influence brain electrical activity in both adults and children. On the basis of the results from our other studies (7 studies), mobile phone does not affect cognitive functions, brain blood flow or metabolism, or subjective symptoms in adults or children.
· The effects of radiofrequency radiation on ODC activity, cell proliferation, and programmed cell death in yeast cells and cultured rodent cell lines were studied at University of Kuopio. The ODC activity was not clearly affected by different radiofrequency exposure levels or durations. However, our results showed some cell type specificity in radiofrequncy effects on ODC activity. More profound effects were found if cells were coexposed to a known stress factors (e.g. ultraviolet radiation, serum deprivation, or oxidative agents) together with radiofrequency fields. In summary, effects of mere radiofrequency radiation on different cell culture models are quite minor but various coexposure approaches warrant additional studies.
· STUK developed further technical methods for exposing cells to GSM mobile phone radiation.The objective was to improve the accuracy in the determination of the power absorbed (SAR) and the temperature rise in cell dishes. The SAR distribution and the temperature rise in the dish was determined by computing with numerical models and by measuring the electric field and the temperature rise in cell dishes. Measurements were carried out with specially constructed sensors.
· Biological studies showed that radiofrequency modulated electromagnetic fields (GSM 900MHz and GSM 1800 MHz) induced a stress response in the cells. In addition, there were changes in the expression and cellular localization of cytoskeletal proteins. These results support previously presented hypotheses of potential changes in the blood-brain barrier.
· Tampere University of Technology, Ragnar Granit Institute has developed anatomical models for estimation of radio frequency absorption dosimetry. Bone, brain tissue etc. have different intrinsic properties to absorb electromagnetic fields. To construct accurate computational models of the head for example the tissue compartments have to be identified. The basis for this is a stack of medical MR images of which certain anatomical tissue structures are identified. During the project a number of head and thorax models were formed
· VTT continued the dosimetric simulations started in the previous project by using expanded and detailed dosimetric computer models of the exposure chambers for laboratory animals and cell cultures.
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Friday, July 4, 2008
Mobile Side-Effects
The high end of the spectrum, ionising radiation, such as that emitted by X-ray machines, has well-known dangers. But the weak signals released by nonionising radio frequencies do not cause DNA damage, and there is no explanation for how such energy could cause cancer, McCormick says.
Most studies have not consistently demonstrated a link between cellphone use and cancer, including two studies conducted by the National Cancer Institute. Several other studies coordinated through the International Agency for Research on Cancer, called the Interphone studies, have also failed to show an association. Numerous studies on animals have also found no evidence that DNA is damaged by low levels of radio frequency, McCormick says.
But the sheer volume of use, as well as a few studies that found a potential link between brain cancer and cellphones, have kept the safety question looming.
The US National Academy of Sciences released a report in January calling for more research on cellphones and health risks. The authors concluded that many of the past studies were not conducted over a long-enough period of time to assess the risk of brain cancer, which typically develops slowly.
Nor have the studies examined the effects of cellphone use on children, whose nervous systems are still developing, or on whether the radio frequency emissions can cause other types of health problems, such as cancers elsewhere in the body or central nervous system damage that may affect learning or behaviour, says Dr Leeka Kheifets, a professor of epidemiology at the University of California, Los Angeles’ School of Public Health and a member of the NAS panel.
“At this point, it looks unlikely that cellphones are causing brain tumors, particularly from short-term exposures,” says Kheifets. “But we have not looked at all outcomes yet. The focus has been on brain tumors because exposure from cellphone use is mostly to the brain. And we are just beginning some studies on brain cancer in children.”
Kheifets and researchers in Denmark recently examined cellphone use in children and found “unexpected results”.
The researchers examined 13,159 Danish children born in 1997 and 1998 who are participants of a study called the Danish National Birth Cohort. The children’s mothers were surveyed during pregnancy and again when the children were 18 months old and 7 years old.
The study found that children who used cellphones, and whose mothers used cellphones during pregnancy were 80 per cent more likely to have behavioural problems such as emotional symptoms, inattention, hyperactivity and problems with peers compared with children who had no cellphone exposure as foetuses or in early childhood.
Children whose mothers used cellphones during pregnancy but who had no other cellphone exposure were 54 per cent more likely to have behavioural problems. The study, which will be published this month in Epidemiology, is the first to find a behavioural effect and so must be interpreted with caution. But Kheifets says: “In general, children are more susceptible to environmental hazards. We have little information on cellphones, and children are using cell phones at younger ages.”
Research on children and long-term studies should provide more clarification on any health risks, says Dr Siegal Sadetzki, an epidemiologist at Gertner Institute, Chaim Sheba Medical Center, in Israel. Sadetzki’s research has found heavy cellphone users were at 50 per cent higher risk for a parotid tumor, which arises in the salivary gland near the ear and jaw, typically where cellphones are held. Parotid tumors can be cancerous or benign. The study was significant because it tracked heavy users for more than 10 years and found a relationship between the side of the head the phone was typically placed against and where the tumor formed.
She says she doesn’t think her study, which was published in February in the American Journal of Epidemiology, contradicts previous studies that showed no cause for alarm. The research was conducted in Israel, which has a population of heavy users who were among the first to adopt cellphone technology.
“Most negative results were seen for short-term users, below 10 years of use,” she said in an e-mail interview. “It is well known that the latency period for cancer development, and certainly for brain tumor development, is longer. The problem is, of course, that we are dealing with a relatively new technology.”
Besides the recent studies that have found some cause for concern, the controversy over cellphone safety was stoked recently when an Australian neurosurgeon published a paper on the Internet saying phone use “has far broader public health ramifications than asbestos and smoking”.
The doctor, Vini Khurana, analysed data from over 100 studies, concluding that most weren’t long enough to uncover a risk of brain cancer and that children haven’t been adequately studied. His Internet paper and recent appearance on CNN’s “Larry King Live” show rankled some health experts because of his alarming stance.
“The position he took was rather extreme,” says McCormick.
King’s show was followed with a blog posting on cnn.com by the network’s chief medical correspondent, Dr Sanjay Gupta, who also appeared on the show. The item cast doubt on cellphone safety and noted that both Khurana and Dr Keith Black, a neurosurgeon at Cedars-Sinai Medical Center who appeared on King’s show, use hands-free cellphone devices. A spokesperson for Black says he is no longer commenting publicly on potential cellphone hazards.
Says Sadetzki: “I believe that the cellphone technology has a lot of advantages and is here to stay. But we, as a society, need to decide how to use it. The precautionary principle advising the use of simple measures to lower exposure should be adopted and taken seriously.”
Most studies have not consistently demonstrated a link between cellphone use and cancer, including two studies conducted by the National Cancer Institute. Several other studies coordinated through the International Agency for Research on Cancer, called the Interphone studies, have also failed to show an association. Numerous studies on animals have also found no evidence that DNA is damaged by low levels of radio frequency, McCormick says.
But the sheer volume of use, as well as a few studies that found a potential link between brain cancer and cellphones, have kept the safety question looming.
The US National Academy of Sciences released a report in January calling for more research on cellphones and health risks. The authors concluded that many of the past studies were not conducted over a long-enough period of time to assess the risk of brain cancer, which typically develops slowly.
Nor have the studies examined the effects of cellphone use on children, whose nervous systems are still developing, or on whether the radio frequency emissions can cause other types of health problems, such as cancers elsewhere in the body or central nervous system damage that may affect learning or behaviour, says Dr Leeka Kheifets, a professor of epidemiology at the University of California, Los Angeles’ School of Public Health and a member of the NAS panel.
“At this point, it looks unlikely that cellphones are causing brain tumors, particularly from short-term exposures,” says Kheifets. “But we have not looked at all outcomes yet. The focus has been on brain tumors because exposure from cellphone use is mostly to the brain. And we are just beginning some studies on brain cancer in children.”
Kheifets and researchers in Denmark recently examined cellphone use in children and found “unexpected results”.
The researchers examined 13,159 Danish children born in 1997 and 1998 who are participants of a study called the Danish National Birth Cohort. The children’s mothers were surveyed during pregnancy and again when the children were 18 months old and 7 years old.
The study found that children who used cellphones, and whose mothers used cellphones during pregnancy were 80 per cent more likely to have behavioural problems such as emotional symptoms, inattention, hyperactivity and problems with peers compared with children who had no cellphone exposure as foetuses or in early childhood.
Children whose mothers used cellphones during pregnancy but who had no other cellphone exposure were 54 per cent more likely to have behavioural problems. The study, which will be published this month in Epidemiology, is the first to find a behavioural effect and so must be interpreted with caution. But Kheifets says: “In general, children are more susceptible to environmental hazards. We have little information on cellphones, and children are using cell phones at younger ages.”
Research on children and long-term studies should provide more clarification on any health risks, says Dr Siegal Sadetzki, an epidemiologist at Gertner Institute, Chaim Sheba Medical Center, in Israel. Sadetzki’s research has found heavy cellphone users were at 50 per cent higher risk for a parotid tumor, which arises in the salivary gland near the ear and jaw, typically where cellphones are held. Parotid tumors can be cancerous or benign. The study was significant because it tracked heavy users for more than 10 years and found a relationship between the side of the head the phone was typically placed against and where the tumor formed.
She says she doesn’t think her study, which was published in February in the American Journal of Epidemiology, contradicts previous studies that showed no cause for alarm. The research was conducted in Israel, which has a population of heavy users who were among the first to adopt cellphone technology.
“Most negative results were seen for short-term users, below 10 years of use,” she said in an e-mail interview. “It is well known that the latency period for cancer development, and certainly for brain tumor development, is longer. The problem is, of course, that we are dealing with a relatively new technology.”
Besides the recent studies that have found some cause for concern, the controversy over cellphone safety was stoked recently when an Australian neurosurgeon published a paper on the Internet saying phone use “has far broader public health ramifications than asbestos and smoking”.
The doctor, Vini Khurana, analysed data from over 100 studies, concluding that most weren’t long enough to uncover a risk of brain cancer and that children haven’t been adequately studied. His Internet paper and recent appearance on CNN’s “Larry King Live” show rankled some health experts because of his alarming stance.
“The position he took was rather extreme,” says McCormick.
King’s show was followed with a blog posting on cnn.com by the network’s chief medical correspondent, Dr Sanjay Gupta, who also appeared on the show. The item cast doubt on cellphone safety and noted that both Khurana and Dr Keith Black, a neurosurgeon at Cedars-Sinai Medical Center who appeared on King’s show, use hands-free cellphone devices. A spokesperson for Black says he is no longer commenting publicly on potential cellphone hazards.
Says Sadetzki: “I believe that the cellphone technology has a lot of advantages and is here to stay. But we, as a society, need to decide how to use it. The precautionary principle advising the use of simple measures to lower exposure should be adopted and taken seriously.”
Mobile Effects today
Drivers who use hands-free cellular devices while driving may be doing themselves a favor in the long run. That’s because scientists still can’t say with certainty that placing a cellphone against the head is completely safe, especially for heavy users and people who began using the devices as children.
They point to lingering questions over potential health effects from the energy emitted by the phones, specifically the long-debated risk of developing brain cancer. “It’s fair to say that the data aren’t all in yet,” says Dr David L McCormick, a biologist and director of the Illinois Institute of Technology Research Institute in Chicago, who has studied the issue. “There are a small number of epidemiological studies that have suggested a possible increase in cancer risk. But comparable studies in other populations haven’t confirmed these findings.”
That’s not to say anyone should panic. Cellphones do produce a type of radiation, but it’s of the type called nonionising radio frequency — a form of energy located on the electromagnetic spectrum.
At the high end of the spectrum, ionising radiation, such as that emitted by X-ray machines, has well-known dangers. But the weak signals released by nonionising radio frequencies do not cause DNA damage, and there is no explanation for how such energy could cause cancer, McCormick says.
Most studies have not consistently demonstrated a link between cellphone use and cancer, including two studies conducted by the National Cancer Institute. Several other studies coordinated through the International Agency for Research on Cancer, called the Interphone studies, have also failed to show an association. Numerous studies on animals have also found no evidence that DNA is damaged by low levels of radio frequency, McCormick says.
But the sheer volume of use, as well as a few studies that found a potential link between brain cancer and cellphones, have kept the safety question looming.
The US National Academy of Sciences released a report in January calling for more research on cellphones and health risks. The authors concluded that many of the past studies were not conducted over a long-enough period of time to assess the risk of brain cancer, which typically develops slowly.
Nor have the studies examined the effects of cellphone use on children, whose nervous systems are still developing, or on whether the radio frequency emissions can cause other types of health problems, such as cancers elsewhere in the body or central nervous system damage that may affect learning or behaviour, says Dr Leeka Kheifets, a professor of epidemiology at the University of California, Los Angeles’ School of Public Health and a member of the NAS panel.
“At this point, it looks unlikely that cellphones are causing brain tumors, particularly from short-term exposures,” says Kheifets. “But we have not looked at all outcomes yet. The focus has been on brain tumors because exposure from cellphone use is mostly to the brain. And we are just beginning some studies on brain cancer in children.”
Kheifets and researchers in Denmark recently examined cellphone use in children and found “unexpected results”.
The researchers examined 13,159 Danish children born in 1997 and 1998 who are participants of a study called the Danish National Birth Cohort. The children’s mothers were surveyed during pregnancy and again when the children were 18 months old and 7 years old.
The study found that children who used cellphones, and whose mothers used cellphones during pregnancy were 80 per cent more likely to have behavioural problems such as emotional symptoms, inattention, hyperactivity and problems with peers compared with children who had no cellphone exposure as foetuses or in early childhood.
Children whose mothers used cellphones during pregnancy but who had no other cellphone exposure were 54 per cent more likely to have behavioural problems. The study, which will be published this month in Epidemiology, is the first to find a behavioural effect and so must be interpreted with caution. But Kheifets says: “In general, children are more susceptible to environmental hazards. We have little information on cellphones, and children are using cell phones at younger ages.”
Research on children and long-term studies should provide more clarification on any health risks, says Dr Siegal Sadetzki, an epidemiologist at Gertner Institute, Chaim Sheba Medical Center, in Israel. Sadetzki’s research has found heavy cellphone users were at 50 per cent higher risk for a parotid tumor, which arises in the salivary gland near the ear and jaw, typically where cellphones are held. Parotid tumors can be cancerous or benign. The study was significant because it tracked heavy users for more than 10 years and found a relationship between the side of the head the phone was typically placed against and where the tumor formed.
She says she doesn’t think her study, which was published in February in the American Journal of Epidemiology, contradicts previous studies that showed no cause for alarm. The research was conducted in Israel, which has a population of heavy users who were among the first to adopt cellphone technology.
“Most negative results were seen for short-term users, below 10 years of use,” she said in an e-mail interview. “It is well known that the latency period for cancer development, and certainly for brain tumor development, is longer. The problem is, of course, that we are dealing with a relatively new technology.”
Besides the recent studies that have found some cause for concern, the controversy over cellphone safety was stoked recently when an Australian neurosurgeon published a paper on the Internet saying phone use “has far broader public health ramifications than asbestos and smoking”.
The doctor, Vini Khurana, analysed data from over 100 studies, concluding that most weren’t long enough to uncover a risk of brain cancer and that children haven’t been adequately studied. His Internet paper and recent appearance on CNN’s “Larry King Live” show rankled some health experts because of his alarming stance.
“The position he took was rather extreme,” says McCormick.
They point to lingering questions over potential health effects from the energy emitted by the phones, specifically the long-debated risk of developing brain cancer. “It’s fair to say that the data aren’t all in yet,” says Dr David L McCormick, a biologist and director of the Illinois Institute of Technology Research Institute in Chicago, who has studied the issue. “There are a small number of epidemiological studies that have suggested a possible increase in cancer risk. But comparable studies in other populations haven’t confirmed these findings.”
That’s not to say anyone should panic. Cellphones do produce a type of radiation, but it’s of the type called nonionising radio frequency — a form of energy located on the electromagnetic spectrum.
At the high end of the spectrum, ionising radiation, such as that emitted by X-ray machines, has well-known dangers. But the weak signals released by nonionising radio frequencies do not cause DNA damage, and there is no explanation for how such energy could cause cancer, McCormick says.
Most studies have not consistently demonstrated a link between cellphone use and cancer, including two studies conducted by the National Cancer Institute. Several other studies coordinated through the International Agency for Research on Cancer, called the Interphone studies, have also failed to show an association. Numerous studies on animals have also found no evidence that DNA is damaged by low levels of radio frequency, McCormick says.
But the sheer volume of use, as well as a few studies that found a potential link between brain cancer and cellphones, have kept the safety question looming.
The US National Academy of Sciences released a report in January calling for more research on cellphones and health risks. The authors concluded that many of the past studies were not conducted over a long-enough period of time to assess the risk of brain cancer, which typically develops slowly.
Nor have the studies examined the effects of cellphone use on children, whose nervous systems are still developing, or on whether the radio frequency emissions can cause other types of health problems, such as cancers elsewhere in the body or central nervous system damage that may affect learning or behaviour, says Dr Leeka Kheifets, a professor of epidemiology at the University of California, Los Angeles’ School of Public Health and a member of the NAS panel.
“At this point, it looks unlikely that cellphones are causing brain tumors, particularly from short-term exposures,” says Kheifets. “But we have not looked at all outcomes yet. The focus has been on brain tumors because exposure from cellphone use is mostly to the brain. And we are just beginning some studies on brain cancer in children.”
Kheifets and researchers in Denmark recently examined cellphone use in children and found “unexpected results”.
The researchers examined 13,159 Danish children born in 1997 and 1998 who are participants of a study called the Danish National Birth Cohort. The children’s mothers were surveyed during pregnancy and again when the children were 18 months old and 7 years old.
The study found that children who used cellphones, and whose mothers used cellphones during pregnancy were 80 per cent more likely to have behavioural problems such as emotional symptoms, inattention, hyperactivity and problems with peers compared with children who had no cellphone exposure as foetuses or in early childhood.
Children whose mothers used cellphones during pregnancy but who had no other cellphone exposure were 54 per cent more likely to have behavioural problems. The study, which will be published this month in Epidemiology, is the first to find a behavioural effect and so must be interpreted with caution. But Kheifets says: “In general, children are more susceptible to environmental hazards. We have little information on cellphones, and children are using cell phones at younger ages.”
Research on children and long-term studies should provide more clarification on any health risks, says Dr Siegal Sadetzki, an epidemiologist at Gertner Institute, Chaim Sheba Medical Center, in Israel. Sadetzki’s research has found heavy cellphone users were at 50 per cent higher risk for a parotid tumor, which arises in the salivary gland near the ear and jaw, typically where cellphones are held. Parotid tumors can be cancerous or benign. The study was significant because it tracked heavy users for more than 10 years and found a relationship between the side of the head the phone was typically placed against and where the tumor formed.
She says she doesn’t think her study, which was published in February in the American Journal of Epidemiology, contradicts previous studies that showed no cause for alarm. The research was conducted in Israel, which has a population of heavy users who were among the first to adopt cellphone technology.
“Most negative results were seen for short-term users, below 10 years of use,” she said in an e-mail interview. “It is well known that the latency period for cancer development, and certainly for brain tumor development, is longer. The problem is, of course, that we are dealing with a relatively new technology.”
Besides the recent studies that have found some cause for concern, the controversy over cellphone safety was stoked recently when an Australian neurosurgeon published a paper on the Internet saying phone use “has far broader public health ramifications than asbestos and smoking”.
The doctor, Vini Khurana, analysed data from over 100 studies, concluding that most weren’t long enough to uncover a risk of brain cancer and that children haven’t been adequately studied. His Internet paper and recent appearance on CNN’s “Larry King Live” show rankled some health experts because of his alarming stance.
“The position he took was rather extreme,” says McCormick.
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