MONDAY, Aug. 1 (HealthDay News) -- A new study suggests that the children of mothers exposed to high levels of magnetic fields during pregnancy are at increased risk of developing asthma, findings that are sure to reignite the controversy over the health dangers that might be posed by exposure to power lines and electronics.
Though the study does not establish cause-and-effect, researchers found a strong association between asthma in offspring and pregnant women's exposure to magnetic fields emanating from power lines and household items such as fluorescent lights, copy machines, electric blankets, microwaves and hair dryers.
"If EMFs [electromagnetic fields] truly increase risk as we have shown here, because of the ubiquitous exposure to EMFs the public health risk is serious," said study author Dr. De-Kun Li, a reproductive and perinatal epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif.
The study is published online Aug. 1 in the Archives of Pediatrics and Adolescent Medicine.
Li and his colleagues followed the children of 626 pregnant women in Northern California for up to 13 years. During pregnancy, the women wore a meter for 24 hours that measured their average daily exposure to magnetic fields. Exposure was then divided into three groups: low, medium or high.
Nearly 21 percent of the children, or 130, developed asthma.
Children whose mothers had the highest magnetic field exposure (90th percentile or above) were 3.5 times more likely to have asthma than the kids of moms with the lowest exposure (10th percentile or less), the investigators found.
The children of mothers who were in the middle group for magnetic field exposure were 74 percent more likely to have asthma than kids of moms in the lowest group.
Put another way, about 13.6 percent of children whose mothers had the least exposure to magnetic fi
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