| To estimate the effects of specific parental occupational exposures on the incidence of neuroblastoma, we conducted analyses of data from a large multicenter case-control study. Cases included 538 children diagnosed with neuroblastoma (1992--1994) at any of 139 hospitals that are members of two collaborative clinical trials research groups. One control per each of 504 cases was selected by random-digit telephone dialing, and was matched by age to the case child. Telephone interviews conducted with both parents included a lifetime occupational history, with information on dates of employment, industries, job titles, specific duties, hours per week, materials handled, protective equipment, and exposures to chemicals, electrical equipment or radiation sources. When exposures were reported, detailed data were collected on the form and route of exposure, work activities performed when exposed, hours per week and duration of exposure, and the average distance from equipment. For each reported exposure, all available information was evaluated under the guidance of an industrial hygienist, to reclassify parents with improbable exposures. Quantitative average occupational extremely low frequency (ELF) magnetic field (MF) exposure was estimated using a job exposure matrix compiled from values published in the literature. The exposure odds ratio was calculated to estimate the incidence rate ratio of neuroblastoma associated with each parent's exposure. In addition, heterogeneity of effect estimates by MYCN amplification, tumor stage, and age of diagnosis were examined. All paternal exposures were evaluated using hierarchical regression modeling to adjust each estimate toward its prespecified prior distribution. Paternal exposures to diesel fuel, thinner solvents, solder, grain dust, and wood dust were positively associated with neuroblastoma in offspring in all analyses and across all clinical and genetic subtypes. In addition, paternal ELF MF exposure >4.0 milligauss was weakly associated with neuroblastoma. Maternal exposure were infrequent, but there was no evidence of positive associations with chemical exposures or with ELF fields. Maternal exposures to types of equipment that produce radiofrequency and ionizing radiation were positively associated with neuroblastoma, although the estimates were very imprecise. Further research into specific paternal chemical exposures, and to maternal and paternal exposures to radiofrequency fields seems warranted. |
