Background: The aim was to investigate possible associations between glioma (an aggressive type of brain cancer)
and occupational exposure to selected agents: combustion products (diesel and gasoline exhaust emissions, benzo
(a)pyrene), dusts (animal dust, asbestos, crystalline silica, wood dust) and some other chemical agents
(formaldehyde, oil mist, sulphur dioxide).
Methods: The INTEROCC study included cases diagnosed with glioma during 2000?2004 in sub-regions of seven
countries. Population controls, selected from various sampling frames in different centers, were frequency or
individually matched to cases by sex, age and center. Face-to-face interviews with the subject or a proxy
respondent were conducted by trained interviewers. Detailed information was collected on socio-economic and
lifestyle characteristics, medical history and work history. Occupational exposure to the 10 selected agents was
assessed by a job exposure matrix (JEM) which provides estimates of the probability and level of exposure for
different occupations. Using a 25 probability of exposure in a given occupation in the JEM as the threshold for
considering a worker exposed, the lifetime prevalence of exposure varied from about 1 to about 15 for the
different agents. Associations between glioma and each of the 10 agents were estimated by conditional logistic
regression, and using three separate exposure indices: i) ever vs. never; ii) lifetime cumulative exposure; iii) total
duration of exposure.
Results: The study sample consisted of 1,800 glioma cases and 5,160 controls. Most odds ratio estimates were close
to the null value. None of the ten agents displayed a significantly increased odds ratio nor any indication of
dose?response relationships with cumulative exposure or with duration of exposure.
Conclusion: Thus, there was no evidence that these exposures influence risk of glioma.