In other words, about 13% of children born to women in the group with the lowest EMF exposures developed asthma compared to about 33% of children born to women who had high EMF exposures.
“That’s a striking figure,” says David Savitz, PhD, a professor of community health and obstetrics and gynecology at Brown University in Providence, R.I. “That magnitude of association we don’t see very often. If it was correct, and that’s a big ‘if,’ that would be really startling.”
But Savitz and others acknowledge that all research has to start somewhere.
“There are a lot of important topics that started out looking pretty flaky and pretty unlikely. There was a time when it made no sense that smoking could be bad for you,” he says.
Other experts agree. “The study appears to be well executed and the finding is surprising,” says Jonathan M. Samet, MD, a pulmonologist and epidemiologist at the Keck School of Medicine at the University of Southern California in Los Angeles.Samet recently led a World Health Organization panel that concluded that EMFs from cell phones and other wireless devices could possibly cause cancer.
Linking EMFs to Asthma in Kids
Researchers asked pregnant women who were members of the Kaiser Permanente Northern California health plan to wear magnetic field sensors around their waists for 24 hours.
The sensors took readings every 10 seconds, recording magnetic field levels of everything the women came into contact with during the day.
The sensors measured low frequency magnetic fields, which are generated by things like refrigerators, vacuum cleaners, hair dryers, cars, power lines, stoves, microwaves, computers, nearly anything that can be plugged in or runs on a motor.
Researchers then ranked those readings from the highest to lowest and picked out the middle number as a way to judge exposure.
Researchers don’t know why some women had higher exposures while others had lower exposures, but Savitz says roughly 10% to 20% of households in the U.S. would meet the criteria for high EMF exposures used in the study.
Researchers then followed the women and their children for up to 13 years. Children were considered to have asthma if a doctor diagnosed them with the condition twice in the same year.
Compared to children of mothers in the low magnetic field group, who developed asthma at rates that were roughly comparable to the national average, those in the high group had a 350% increased risk of getting the condition, while those in the medium group had a 74% increased risk.
The association remained even after researchers adjusted their data for things that might independently influence the development of asthma in kids, like age, sex, early birth, low birth weight, breastfeeding, and a family history of the condition.
“The great thing about EMF is that distance really helps,” Li says. For example, “When you turn the microwave on, don’t stand right next to it. Try to, when you use a hair dryer, try to use it far away from your tummy as much as you can.”
In the case of can openers, opting for a hand crank device, rather than an electric one, can lower EMF exposure.