Objectives The aetiology of glioma remains unknown. Occupational exposure to chemicals and other agents have been previously explored as possible risk factors with mixed findings in the literature. This analysis aimed to explore associations between lifetime occupational exposure to selected agents and glioma risk. An adapted version of a Finnish job exposure matrix (FINJEM) was applied to coded occupational histories collected as part of a large, international case-control study.
Methods A case-control study was carried out in seven countries with lifetime occupational histories available for 2058 cases and 5813 controls. Occupational exposure estimates to twenty nine agents categorised into five broad groups (dust (n=4), solvents (n=11), metals (n=5), combustions products (n=6) and others (n=3)) were applied to all occupations held per individual. Statistical analysis was carried out using unconditional logistic regression, stratified by age, sex and study centre. Several indices of exposure were investigated (ever/never, quintiles, cumulative exposure) and analyses were repeated by sex.
Results Estimated exposure to any of the chemical agents included in INTEROCC was over 80% for benzo(a)pyrene and polycyclic aromatic hydrocarbons due to environmental tobacco smoke exposure. For other exposures percentages varied between 0.7% (sulphur dioxide) and 18% (asbestos) for control participants. No significant relationship with glioma risk was found between estimated occupational exposures for any of the chemical agents considered.
Conclusions Lifetime occupational exposure to the chemicals explored was not found to be associated with risk of glioma. Additional analyses relating to time windows of exposure and grouping exposures will also be carried out.