Objectives The purpose of the study was to address the possible associations between the occupational exposure of men to electromagnetic fields (EMF) and the risk of childhood brain tumors in offspring by reanalyzing case-referent interview data from a study of environmental factors and childhood brain tumors conducted by one of the authors and first reported in 1990.

Methods Analyses of the case-referent data were limited to the 94 cases and 166 individually-matched referents for whom data on the biological fathers were available. Paternal exposure to occupational EMF was inferred from a list of job titles compiled for that purpose. Mantel-Haenszel odds ratios (OR) for individually matched cases and referents were estimated for different definitions of exposure.

Results The findings suggested at best very small increases in risk for jobs associated with the occupational EMF exposure of fathers during the one-year period prior to conception, the OR values ranging from 1.12 to 1.31. Notably elevated OR values were, however, found in association with any paternal welding in the one-year preconception period (OR 3.8, 95% confidence interval 0.95 -- 15.55).

Conclusion The results of reanalysis indicate that preconceptional paternal occupational exposure to EMF is at best only weakly associated with a risk of childhood brain tumors. However, the findings for paternal welding are somewhat intriguing since relatively strong EMF have been measured in association with welding. Further study of welding as a potential risk factor is required since welders may be exposed to a wide range of toxic agents in addition to EMF.

Key terms adverse effect; brain neoplasm; electromagnetic fields; epidemiology; occupational exposure