An investigation of brain tumors among chemical plant employees using a sample-based cohort method.
Reeve GR; Bond GG; Lloyd JW; Cook RR; Waxweiler RJ; Fishbeck WA
J Occup Med 1983 May; 25(5):387-393
A sample based cohort study of brain tumors in employees of a chemical production facility was conducted. Risk estimates of death due to brain tumors were calculated for production and non production employees. Observed deaths were identified by using a four contiguous county record linkage process. The sample included 1,666 white males employed between 1940 and 1977. Three separate estimates of expected deaths were calculated. The first assumed no migration of the sample cohort members. The other two methods considered migration, one by a NIOSH procedure and the other by a procedure developed by company epidemiologists. A total of 25 brain tumor deaths among former employees was observed. Seventeen of the 25 were among employees hired from 1940 through 1943. The average age at hire of the brain tumor decedents compared closely with that of the study cohort. The observed deaths were divided by estimates of expected deaths and multiplied by 100 to yield standardized mortality ratios (SMRs). Three sets of sample based SMRs were calculated. The first method gave an SMR of 57; the NIOSH migration method yielded an SMR of 126; and the other migration method showed an SMR of 118. The two migration adjusted SMRs appeared closer to each other than to the unadjusted first method. For those hired before 1945, SMRs were 78 for the unadjusted method and 184 for both migration adjusted methods. The authors conclude that this study suggests a slight increased risk of death due to brain tumors for the chemical facility employees, with a probable increased risk for those hired before 1945. The sample based method with a regional record linkage process is an efficient use of resources.
JOCMA7; NIOSH-Author; Tumorigenesis; Toxic-effects; Occupational-exposure; Industrial-exposures; Breathing; Exposure-limits; Industrial-chemicals; Workers; Industrial-environment; Chemical-analysis; Tumorigens
Journal of Occupational Medicine