RT Journal Article SR Electronic T1 Interactions between occupational exposure to extremely low frequency magnetic fields and chemicals for brain tumour risk in the INTEROCC study JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP oemed-2016-104080 DO 10.1136/oemed-2016-104080 A1 Michelle C Turner A1 Geza Benke A1 Joseph D Bowman A1 Jordi Figuerola A1 Sarah Fleming A1 Martine Hours A1 Laurel Kincl A1 Daniel Krewski A1 Dave McLean A1 Marie-Elise Parent A1 Lesley Richardson A1 Siegal Sadetzki A1 Klaus Schlaefer A1 Brigitte Schlehofer A1 Joachim Schüz A1 Jack Siemiatycki A1 Martie van Tongeren A1 Elisabeth Cardis YR 2017 UL http://oem.bmj.com/content/early/2017/06/09/oemed-2016-104080.abstract AB Objectives In absence of clear evidence regarding possible effects of occupational chemical exposures on brain tumour aetiology, it is worthwhile to explore the hypothesis that such exposures might act on brain tumour risk in interaction with occupational exposure to extremely low frequency magnetic fields (ELF).Methods INTEROCC is a seven-country (Australia, Canada, France, Germany, Israel, New Zealand and UK), population-based, case–control study, based on the larger INTERPHONE study. Incident cases of primary glioma and meningioma were ascertained from 2000 to 2004. Job titles were coded into standard international occupational classifications and estimates of ELF and chemical exposures were assigned based on job-exposure matrices. Dichotomous indicators of cumulative ELF (≥50th vs <50th percentile, 1–4 year exposure time window) and chemical exposures (ever vs never, 5-year lag) were created. Interaction was assessed on both the additive and multiplicative scales.Results A total of 1939 glioma cases, 1822 meningioma cases and 5404 controls were included in the analysis, using conditional logistic regression. There was no clear evidence for interactions between ELF and any of the chemical exposures assessed for either glioma or meningioma risk. For glioma, subjects in the low ELF/metal exposed group had a lower risk than would be predicted from marginal effects. Results were similar according to different exposure time windows, to cut-points of exposure or in exposed-only analyses.Conclusions There was no clear evidence for interactions between occupational ELF and chemical exposures in relation to glioma or meningioma risk observed. Further research with more refined estimates of occupational exposures is recommended.