Analysis A study of 913 pregnant women in the San Francisco Bay Area, California, found those exposed to high levels of magnetic field (MF) non-ionizing radiation had a 2.72x higher risk of miscarriage than those exposed to low MF levels.
The Kaiser Permanente study, “Exposure to Magnetic Field Non-Ionizing Radiation and the Risk of Miscarriage: A Prospective Cohort Study,” was published this month in the journal Scientific Reports.
The authors, Kaiser researchers De-Kun Li, Hong Chen, Jeannette R. Ferber, Roxana Odouli, and Charles Quesenberry, say their findings add to the evidence that “MF non-ionizing radiation could have adverse biological impacts on human health.”
Mobile phones and Wi-Fi transmitters fire out radio-frequency MF radiation, but are not the only sources of such emissions; as such the study should not be construed as a specific indictment of those devices. Indeed, rather worry solely about smartphones or wireless networks peppering you with radiation, being surrounded by everyday electrical things – from fridges and freezers to hairdryers and clothes irons – may be more harmful than you may think. Possibly.
“In this study, we found an almost three-fold increased risk of miscarriage if a pregnant woman was exposed to higher MF levels compared to women with lower MF exposure,” the study says. “The association was independent of any specific MF exposure sources or locations, thus removing the concern that other factors connected to the sources of the exposure might account for the observed associations.”
Study participants were classified in four MF exposure groups – <2.5mG; 2.5–3.6mG; 3.7–6.2mG; and ≥6.3mG – based on 24 hours of measurements with an EMDEX Lite meter as a representation of daily exposure. The researchers did not find the miscarriage risk increased with doses above 2.5mG, leading them to theorize that 2.5mG represents a threshold level for health effects.
In an email to The Register, Dr De-Kun Li, senior research scientist at the research division of Kaiser Permanente Northern California, said: “Please keep in mind that our study was not specifically designed to study radio-frequency magnetic fields, which are more applicable to cell phones and Wi-Fi. Also, we are at an early stage in understanding the health effects of magnetic fields; this is not a settled issue.”
Li said past studies of magnetic fields suffered from poor methods of measurement.
“The controversy over health effects from electromagnetic fields is, to a large extent, a product of earlier studies that did not find many associations between EMF and health risk,” he said. “Looking back, the main reason for the ‘negative findings’ is that those studies were not able to actually measure EMF exposure. When one can’t measure an exposure (e.g., EMF), the ‘study finding,’ by definition, won’t be able to find any association, thus negative findings. This applies to any study, not just those related to EMF. (For example, if one can’t measure the amount of calorie intake, one would conclude that calorie intake has nothing to do with being overweight.)”
Li said his group’s study supports the previously reported association between exposure to high MF levels in pregnancy and the risk of miscarriage, which has been suggested in at least seven other studies.
As Li observed, there is no scientific consensus that MF exposure harms human health. According to the National Cancer Institute, “[A]lthough many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk.”
The Kaiser researchers contend that the focus on studying the effect of MF radiation on cancer has made a more general focus on other health effects more difficult because the length of time required before cancer develops has led to inconclusive studies and has supported the impression that MF is entirely safe.
Others organizations are showing more concern too. Last week, the California Department of Public Health took the unusual step of issuing guidelines on how to reduce exposure to radio frequency energy.
In a statement, CDPH director Dr Karen Smith said, “Although the science is still evolving, there are concerns among some public health professionals and members of the public regarding long-term, high use exposure to the energy emitted by cell phones.”
The CDPH is now recommending that adults and particularly children take steps to keep phones away from their bodies, particularly when asleep. The agency also suggests removing headsets when not making calls.
Moreover, the agency advises against using products that purport to block radio frequency energy because such products “may actually increase your exposure.”
In an email to The Register, a spokesperson for the CDPH said the publication of the Kaiser study and the CDPH guidelines during the same week as a coincidence.
“Within the last two years, more evidence has emerged documenting changing patterns of cell phone use – cell phone use is increasing overall and, importantly, we are seeing increased use among young children,” the CDPH spokesperson said. “The overall increase in usage, especially when paired with lower age of use, is significant. It is in this context, and in response to growing concern among some members of the public that we are releasing this guidance.”
The CDPH spokesperson said the science is still evolving and the CDPH continues to study and monitor the data.
Asked whether there is any particular health condition that has been affirmatively associated with exposure to high levels of MF, the CDPH spokesperson said, as per agency guidance, “studies do not establish a definite link and scientists disagree about whether cell phones cause certain health problems and how great the risks might be.”
If there is a correlation between MF exposure and adverse health outcomes, the effects may be harder to avoid than moving phones away from nightstands and turning off the Wi-Fi network. Electronic appliances of all sorts emit MF radiation. For example, at a distance of one-inch, a clothes iron emits 80-300mG of MF radiation, and an electric blanket emits 3-50mG.
A 2002 report published by the National Institute of Environmental Health Sciences indicates that 6.3 per cent of people in the US are exposed to more than 3mG of MF radiation in a 24-hour period.
Given the levels measured in the Kaiser study, the proliferation of mobile phones and Wi-Fi devices appear to have increased the average level of exposure in the US.
Ionizing radiation, such as X-rays, has long been known to have adverse health effects because it has enough energy to interact with human biology. Even so, the National Institute for Occupational Safety and Health (NIOSH) cautions we don’t really know what causes health problems that could be linked to ionizing radiation.
For example, airline crew members get an estimated annual average dose of cosmic ionizing radiation – ionizing radiation from space – that’s three times higher (3.07 mSv) than the general public, according to the National Institute for Occupational Safety and Health.
A study of pregnant flight attendants by NIOSH found that those exposed to 0.36mSv or more of ionizing radiation in the first trimester were at greater risk of miscarriage.
Yet NIOSH offers an out, as if to immunize airlines from lawsuits: “If you are exposed to cosmic ionizing radiation and have these health problems, we can’t tell if it was caused by your work conditions or something else.”
The same can be said about miscarriages and MF exposure.
Non-ionizing radiation has been generally regarded as safe at common exposure levels, at least among reputable studies. But the Kaiser study, along with other recent research, suggests further need to challenge that assumption.
Mobile industry trade group CTIA did not respond to a request for comment.
For those concerned about MF exposure, Li advised separation. “If anyone is concerned about the potential health risks from magnetic field non-ionizing radiation, one can take some simple precautionary steps such as keeping at a distance from the sources,” he said. “In this case, distance is your friend.” ®