Case-control study of intracranial tumors among employees at a petrochemical research facility.

This case-control study evaluated the relation between potential exposure to chemical and physical agents and the occurrence of intracranial tumors among employees at a petrochemical research facility. Cases were employees with glioma (n = 6) or benign intracranial tumors (n = 6). Controls (n = 119) were individually matched to cases on gender and birth year, and they were alive and did not have an intracranial tumor at the case's diagnosis date. Exposure information came from interviews with subjects or surrogates and from corporate records on agents used in research projects. Analyses computed matched odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for self-reported exposure to 15 agents and project-based estimates of exposure to 29 agents. For gliomas, the OR was elevated for self-reported exposure to ionizing radiation (OR, 15.7; CI, 1.4 to 179.4), n-hexane (OR, infinity; CI, 1.4 to infinity), organometallics (OR, 9.4; CI, 1.5 to 59.7), and amines other than nitrosamines (OR, 6.0; CI, 1.0 to 35.7). The OR also was elevated for project-based potential use of ionizing radiation (OR, 9.6; CI, 1.7 to 55.2) and for potential use of n-hexane lasting at least 4 years (OR, 16.2; CI, 1.1 to 227.6). For benign intracranial tumors, the OR was elevated only for self-reported exposure to ionizing radiation (OR, 5.4; CI, 1.7 to 43.1) and other amines (OR, 5.2; CI, 0.9 to 29.5). Occupational exposure may have contributed to the glioma excess, but the specific causal agents remain unknown. The study indicated that benign intracranial tumors were unlikely to be work-related.

Case-series investigation of intracranial neoplasms at a petrochemical research facility.

BACKGROUND: From 1970 through 1997, 17 intracranial neoplasms were identified among 6,800 employees of a petrochemical research facility. This investigation describes the case-series. METHODS: The intracranial neoplasms were identified by self reports and record linkages, and were confirmed by medical records and a pathology review. Standardized incidence ratios (SIRs) compare observed and expected numbers of cases according to certain work characteristics. RESULTS: Overall, there were 17 observed and 10.5 expected intracranial neoplasms, including 11/4.7 benign intracranial tumors and 6/5.9 brain cancers. All brain cancers occurred among male research scientists or technicians. Four had worked at some time on the same floor of one building (SIR=12.6, 95% CI=3.4-32.1), and several had worked on a research project with at least one other brain cancer case. The benign intracranial neoplasm cases did not have common building assignments or work activities. CONCLUSIONS: The occurrence pattern of brain cancers, but not that of benign tumors, suggests a possible occupational etiology.