Study Finds Magnetic Fields Increase Asthma Risk

August 2, 2011 by staff 

Study Finds Magnetic Fields Increase Asthma RiskStudy Finds Magnetic Fields Increase Asthma Risk, Women with high exposure to magnetic fields during pregnancy may be at increased risk of asthma in children, according to a Kaiser Permanente study published online in the journal Archives of Pediatrics & Adolescent Medicine.

In this prospective study, researchers compared the daily magnetic field exposure at 801 pregnant Kaiser Permanente Northern California and used electronic medical records to track their children for 13 years to see that the children developed asthma. The study found that women with exposure to magnetic fields during pregnancy were more than threefold risk of asthma in their children compared with mothers whose exposure level is low.

This is the first study to demonstrate a link between the mother’s magnetic field exposure during pregnancy and the risk of asthma in children. Previous research has found that magnetic fields – usually generated by power lines and appliances such as microwave ovens, hair dryers and vacuum cleaners – could lead to the quality of miscarriage, sperm, immune disorders and certain cancers. Recently, the International Agency for Research on Cancer, an agency of the World Health Organization, the radio frequency electromagnetic field classified as a possible carcinogen.

“While the findings need replication, the message here is exposure to electromagnetic fields is not good, and we must pay attention to their adverse health effects,” said study senior author De-Kun Li, MD, PhD, a reproductive and perinatal epidemiologist at Kaiser Permanente Division of Research in Oakland, California, Dr. Li published the original study in 2002 found exposure to magnetic fields can cause miscarriage.

The prevalence of asthma has been increasing since the 1980s, making it the most common chronic disease among children. Thirteen percent of children under 18 have asthma, which is caused by the malfunction of the respiratory organs and the immune system.

“The exposure to EMF is everywhere. Due to the wide exposure, any adverse health effect of EMF could affect many people and cause a serious public health problem,” said Dr. Li.

“The study of EMF health effects has been difficult because we are all exposed to EMFs at some level, that is not true” control group not exposed “to facilitate comparison, the researchers said. Healths researchers must based on a comparison of those with high levels of EMF exposure to those with low levels of exposure to EMFs EMF detect potential adverse effects, “said Dr. Li.

Women in this study used a small meter during your pregnancy to measure their daily exposure to low frequency magnetic fields from sources related to electricity, such as microwave ovens, hair dryers, vacuum cleaners, fans, lamps, coffee grinders and fluorescent, power lines and transformer stations. This study did not measure high-frequency (RF) magnetic fields of wireless networks, towers and wireless devices such as cell phones and smart meters. The researchers adjusted the study participants who lived near the highway, but not change the results of electromagnetic fields and asthma association.

“In this study, we observed a dose-response relationship between the level of the mother from Monday to Friday during pregnancy and the risk of asthma in children. In other words, higher MF exposure during pregnancy breast led to increased risk of asthma in children, “said Dr. Li.

In this new study, researchers also found that two known risk factors for asthma, maternal history of asthma and being the eldest son, exacerbated the effect of CM on the risk of asthma. “This finding supports the association of MF-asthma,” said Dr. Li.

“The best way to reduce their exposure to magnetic fields is distance. Magnetic field strength decreases dramatically with increasing distance from the source,” said Dr. Li. “So pregnant women should try to limit their exposure to known sources of MF and keep a distance from them when in use.”

The study was funded in part by Public Health Foundation of California. Co-authors of the study include Hong Chen, MPH, and Roxanne Odouli, MSPH, both from the Kaiser Permanente Division of Research.

About Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes, and disseminates epidemiological and health services to improve health and medical care of Kaiser Permanente and society in general. It’s about understanding the determinants of illness and wellness and improves the quality and cost-effectiveness of health care. Currently, DOR-400, plus staff is working on more than 250 projects of epidemiological and health research. For more information, visit

About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of the leading U.S. health care providers and nonprofit health plans. Founded in 1945, our mission is to provide high quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve 8.8 million members in nine states and the District of Columbia. Attention members and patients is focused on your overall health and guided by their GPs, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by advances in technology and industry-leading tools for health promotion, disease prevention, and the state of technical assistance and excellent management of chronic diseases. Kaiser Permanente is dedicated to innovations in care, clinical research, health education and health support community. For more information, visit / newscenter.

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