Use of a job-exposure matrix to evaluate parental occupation and childhood cancer.

We examined the association between parental occupation and childhood cancer among 252 incident cases of childhood cancer (ages 0-14, diagnosed 1976-83) and 222 controls selected by random digit dialing in Denver, Colorado (USA). A job-exposure matrix was used to assign parental exposures based on job titles, emphasizing chemicals that were implicated in previous studies. All cancers, acute lymphocytic leukemia (ALL), and brain cancer were examined in relation to parental occupation during the year prior to the birth of the child. Elevated odds ratios (OR), all with confidence intervals extending below the null, were found for maternal exposure to benzene (OR = 1.9), petroleum/coke pitch/tar (OR = 2.2), and soot (OR = 3.3) in relation to total cancers. The ORs for total cancer and paternal exposure to all hydrocarbons combined was 1.0. Results for individual hydrocarbons and ALL showed larger odds ratios, including aniline (OR = 2.1), benzene (OR = 1.6), and petroleum/coke pitch/tar (OR = 1.6). Potential exposure to creosote was strongly associated with brain cancer (OR = 3.7) based on five exposed cases (95 percent confidence interval = 0.8-16.6). Control for other potential childhood cancer risk factors did not alter the results substantially. In spite of uncertainties due to small numbers and errors in exposure classification, results tend to corroborate past research that suggests an association between specific parental occupational exposures and childhood cancer.