Analysis of Nickel Contaminants in Several Groups of Case-Control Sets Generated Within the Falconbridge Mining Cohort

Abstract

The Falconbridge study was a historical prospective mortality study conducted at a nickel company in Sudbury Ontario. The study included all the men that worked there for at least 6 months between 1950 and 1976 with an update in 1984. Nearly 11500 subjects were included in the cohort. From here all the subjects identified with lung cancer were selected and matched with different number of healthy subjects (1:1, 1:2, 1:4, 1:6, 1:8, 1:10). Information was generated of the time-intensity of different contaminants normally found in the mining atmosphere and eight of such contaminants were evaluated for the different sets of case:control. Given the fact that some contaminants present a time delay effect, an assessment of this factor was also made using the subject initial and final time of exposure to each contaminant. Finally a variable selection was performed for the three data sets generated in the project. The results showed that some of the postulated contaminants did have an effect in the final outcome, however, because of the complex effect between the different chemical compounds a definite conclusion is not given.