Detailed job histories and information about other suspected risk factors were 
obtained during interviews with 272 men aged 25-69 with a primary brain tumor 
first diagnosed during 1980-1984 and with 272 individually matched neighbor 
controls. Separate analyses were conducted for the 202 glioma pairs and the 70 
meningioma pairs. Meningioma, but not glioma, was related to having a serious 
head injury 20 or more years before diagnosis [odds ratio (OR) = 2.3; 95% 
confidence interval (CI) = 1.1-5.4], and a clear dose-response effect was 
observed relating meningioma risk to number of serious head injuries (P for 
trend = 0.01; OR for greater than or equal to 3 injuries = 6.2; CI = 1.2-31.7). 
Frequency of full-mouth dental X-ray examinations after age 25 related to both 
glioma (P for trend = 0.04) and meningioma risk (P for trend = 0.06). Glioma, 
but not meningioma risk, related to duration of prior employment in jobs likely 
to involve high exposure to electric and magnetic fields (P for trend = 0.05). 
This risk was greatest for astrocytoma (OR for employment in such jobs for 
greater than 5 years = 4.3; CI = 1.2-15.6). More glioma cases had worked in the 
rubber industry (discordant pairs 6/1) and more worked in hot processes using 
plastics (9/1). More meningioma cases had jobs that involved exposure to metal 
dusts and fumes (discordant pairs 13/5), and six of these cases and two controls 
worked as machinists. Finally, there was a protective effect among glioma pairs 
relating to frequency of use of vitamin C and other vitamin supplements (P for 
trend = 0.004); the OR for use at least twice a day was 0.4 (CI = 0.2-0.8).