Maternal Exposure to Magnetic Field Non-Ionizing Radiation During Pregnancy and the Increased Risk of Allergic Conditions in Offspring: A Longitudinal Cohort Study with up to 22 Years of Follow-up

Abstract

BACKGROUND: Emerging epidemiologic studies and experimental animal studies have reported an impact of magnetic field (MF) non-ionizing radiation on the immune system. We examined the relationship between maternal MF exposure level during pregnancy and the risk of severe allergic conditions, having both asthma and atopic dermatitis (AD), in offspring. METHODS: We enrolled 2,060 pregnant members of Kaiser Permanente Northern California. Consented participants were asked to wear an EMDEX meter for 24 hours in early pregnancy to measure MF exposure levels from all MF-emitting sources. To examine the risk of allergic conditions in offspring, 1,568 participants who delivered a livebirth were included. We used the median of the 24-hour MF measurements to determine maternal MF exposure level. Offspring were followed from birth to early adulthood (up to 22 years) to identify those with clinical diagnoses of both asthma and AD. Confounders were ascertained during in-person interviews. Cox Proportional Hazards regression was used for analysis. RESULTS: After controlling for multiple confounders, a linear dose-response relationship between maternal MF exposure level during pregnancy and the risk of having both asthma and AD in offspring was observed. Every one milligauss (mG) increase of maternal MF exposure was associated with 21 percent increased risk of having both asthma and AD diagnoses in offspring: adjusted hazard ratio (aHR)=1.21, 95% confidence interval (CI): 1.03-1.43. Using categorical measures also showed a statistically significant dose-response relationship (p=0.04). CONCLUSIONS: In this large cohort study with rarely-available objectively measured MF exposure, maternal exposure to high MF levels during pregnancy is associated with an increased risk of having both asthma and AD allergic conditions in offspring. This finding suggests that MF exposure could impact the human immune system, especially the fetal immune system which may be especially vulnerable to the impact of MF non-ionizing radiation. KEYWORDS: Magnetic fields, non-ionizing radiation, allergy