Background: The causes of childhood brain tumors (CBT) are essentially unknown. Exposure to extremely low frequency magnetic fields (ELF-MF) (3-3000Hz) is an ubiquitous part of modern life. However, very few studies have investigated the possible effect of maternal occupational ELF-MF exposure on CBT and the available findings are inconsistent across studies. / Methods: We examined the role of maternal occupational exposure to ELF-MF shortly before and during pregnancy on the incidence of childhood brain tumors. A total of 548 incident cases and 760 healthy controls recruited between 1980 and 2002 from two Canadian provinces (Quebec and Ontario) were included and their mothers were interviewed. Tumors were classified as astroglial tumors, primitive neuroectodermal tumors (PNET), and other gliomas. Quantitative occupational ELF-MF exposure in microtesla units was estimated using individual exposure estimations or a job exposure matrix. We used three metrics to analyze exposure: cumulative, average, and maximum level attained. / Results: Using the average exposure metric measured before conception, an increased risk was observed for astroglial tumors (OR=1.5, and 95% CI=1.0-2.4). During the entire pregnancy period, a significantly increased risk was observed for astroglial tumors as well as for all childhood brain tumors with the average metric (OR=1.6, 95% CI=1.1-2.5 and OR=1.5; 95% CI=1.1-2.2, respectively). Based on job titles, a two-fold risk increase was observed for astroglial tumors (OR=2.3, 95% CI=0.8-6.3) and for all childhood brain tumors (OR=2.3, 95% CI=1.0-5.4) among sewing machine operators. / Conclusion: Results are suggestive of a possible association between maternal occupational ELF-MF exposure and certain brain tumors in their offspring. / Keywords: brain tumors, occupational exposures, maternal exposures, magnetic fields, childhood cancer, job exposure matrix
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.116091 |
| Date | January 2008 |
| Creators | Li, Pei Zhi. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Occupational Health.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 003164029, proquestno: AAIMR67033, Theses scanned by UMI/ProQuest. |
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