New EMF Studies
British Researchers Examine Childhood Cancer Clustering
A large study published in the February 15, 2009 issue of the International Journal of Cancer examined clustering of childhood cancer cases over small areas in Great Britain. First author Richard McNally of Newcastle University and colleagues at the University of Edinburgh and Oxford University aimed to examine whether localized environmental exposures might play an etiologic role in childhood cancer. However, they did not investigate EMF or any other specific exposures. They reported evidence of spatial clustering for acute lymphoblastic leukemia, soft tissue sarcomas, and Wilms tumors, and concluded that common infections may be responsible for the clustering they observed for the first two diseases.
Study Investigates Maternal Occupational Magnetic Field Exposure and Childhood Brain Cancer In a study published in the February 18, 2009 online issue of Cancer Causes Control, Canadian researchers investigated whether mothers' exposure to magnetic fields in the workplace affects brain cancer risk in their children. Researchers Peizhi Li and Claire Infante-Rivard of McGill University and John McLaughlin of the University of Toronto combined data from two case-control studies and compared exposure to extremely low frequency magnetic fields at work shortly before and during pregnancy for the mothers of cases (children with newly diagnosed brain cancer) and the mothers of controls (children without brain cancer). Li et al. reported that although they did not find any strong associations between mothers' occupational magnetic field exposure and the risk of childhood brain tumors, their results suggest a possible association for certain tumors. They concluded that further research with improved exposure assessment is needed.
Study Investigates Residence near Power Lines and Mortality from Neurodegenerative Diseases A Swiss study by Dr. Anke Huss and a team of colleagues at the University of Bern is the first to investigate mortality from neurodegenerative diseases in relation to residence near power lines. The study, published online in the American Journal of Epidemiology on November 5, 2008, reported an increased risk in mortality from Alzheimer's disease and senile dementia among people who lived less than 50 meters from power lines, compared with those who lived at least 600 meters from power lines. Because there is no known biologic mechanism by which EMF from power lines could contribute to the development of these diseases, the authors advise cautious interpretation of these results. Their study found little evidence of increased risk for Parkinson disease, multiple sclerosis, or amyotrophic lateral sclerosis (Lou Gehrig's disease).
Study Investigates Occupational Magnetic Field Exposure and Alzheimer's Disease
A study published online in the journal BMC Neurology on June 9, 2007 examined occupational magnetic field exposure in relation to Alzheimer's disease. The study, by Dr. Zoreh Davanipour and colleagues at the University of Southern California School of Medicine, is an extension of a smaller case-control study published in 1996 by Sobel et al. Both studies report an association between exposure to power-frequency magnetic fields and Alzheimer's disease. Owing to several limitations of the studies, however, the results should be interpreted with caution.
Study Examines Magnetic Field Exposure and Childhood Leukemia Survival in Germany
In 2006 Foliart et al. published the results of an EPRI-sponsored U.S. study that was the first to examine the possible association between residential magnetic field exposure and long-term survival among children with a diagnosis of acute lymphoblastic leukemia (ALL). The study reported that children with exposure to higher measured magnetic fields (above 0.3 microtesla) experienced poorer survival. However, the results were based on very small numbers of leukemia cases with exposures above 0.3 microtesla and are thus imprecise. To further investigate, Drs. Anne Louise Svendsen and Joachim Schüz of the Danish Cancer Society and colleagues at the German Childhood Cancer Registry analyzed survival in relation to magnetic field exposure level for childhood ALL patients in Germany who were enrolled in previous case-control studies of magnetic fields and childhood leukemia. Results were published in the June 2007 issue of the journal Cancer Epidemiology, Biomarkers & Prevention. Although the results are broadly consistent with the results of the U.S. study, they are still based on small numbers. The basis for both reports remains unknown.
Analysis Examines Nighttime Magnetic Field Exposure and Childhood Leukemia
This analysis by Dr. Joachim Schüz (Danish Cancer Society) and a team of colleagues was published online in the American Journal of Epidemiology on May 7, 2007. The team investigated whether magnetic field exposures measured during the night, when children are in their rooms, represent actual exposures more accurately than 24- or 48-hour measurements. If this were the case, the association between magnetic field exposure and childhood leukemia would be expected to be higher in relation to nighttime exposure measurements. The analysis also addressed the hypothesis that nighttime magnetic field exposure might increase cancer risk by reducing normal nocturnal production of the hormone melatonin. The results indicate that nighttime and 24- or 48-hour magnetic field measurements are similar and that childhood leukemia risk in relation to nighttime magnetic field exposure is virtually identical to the risk observed for round-the-clock measurements. These results do not support the melatonin hypothesis.
Study Aims To Measure EMF from Personal Digital Assistants (PDAs)
Personal Digital Assistants (PDAs) are hand-held wireless communication devices that send and receive data (such as voice and e-mail) at radio frequencies. In many units, however, the process of receiving and transmitting radio-frequency (RF) signals also produces extremely low frequency (ELF) fields. In a March 2007 study published online in the journal Bioelectromagnetics, Cindy Sage and colleagues aimed to measure extremely low frequency EMF produced in the immediate proximity of PDAs. However, they neglected to take into account the fact that the EMF measurement meters they used, like all EMF meters, can produce invalid readings in the presence of RF signals. The measurements they report in this study were likely affected by RF interference and cannot be taken to be valid.