Parental occupational exposures and childhood brain tumors

Data from a population-based case-control study in 19 counties in California and Washington State were used to investigate the association between parental occupational exposures and childhood brain tumors. Parents of a total of 540 cases and 801 controls identified from 1984 to 1991 were interviewed for the study, including 308 astroglial and 109 primitive neuroectodermal tumor cases. Parents provided information on industry of employment, job tasks, and occupational substance exposures for jobs held during the five years preceding the birth of the child. In the first stage of analysis, industries and job tasks associated with increased risk for the two most common histologic types of brain tumors (astroglial and primitive neuroectodermal tumors) were identified. In the second stage of analysis, risk was calculated for parental occupational exposure to nitrosamines, chlorinated hydrocarbons, organic solvents, and electromagnetic fields using a job-exposure matrix and worker self-report. Children whose parents worked in the chemical industry were at increased risk of developing astroglial tumors (Fathers' OR = 2.1 95%CI (1.1-3.9) and Mothers' OR = 3.3 (1.4-7.7)). Children of fathers employed as electrical workers were at increased risk of developing brain tumors of any histologic type (OR = 2.3 95%Cl(1.3-4.0)). Elevated odds ratios also were found for fathers working in the retail industry or as salesmen and for children with mothers working in freight handling and packaging, plastic processing, or as stenographers or typists. No association was found between any of the occupational agents and childhood brain tumors based on job exposure matrix data. An increase in risk was found for children of fathers reporting exposure to perchlorethylene or magnetic fields and children of mothers reporting exposure to plastics or magnetic fields. In the final stage of the analysis, we examined the reliability of mothers' proxy responses in comparison to fathers' self-reported employment histories. Proxy respondents (mothers) were able to provide detailed job histories with good agreement for their spouse's non current jobs, but were not able to reliably report exposure to occupational agents.