Canadian Farm Operator Study: methodology

A mortality study of about 326,000 Canadian male farm operators enumerated in the 1971 Census of Agriculture is being conducted by Health and Welfare Canada in collaboration with Statistics Canada. The study examines the mortality patterns of farm operators in relation to farm practices and a variety of socio-demographic variables. The prime concern is the association between pesticide use and certain cancers suggested in previous studies of farmers. This article describes the methodology used to create the study cohort and the analysis files. Highlights of the preliminary results from this study for Saskatchewan are also presented. Results for other regions are forthcoming. Among the Saskatchewan cohort of farm operators, 94% of deaths occurred within the province. The average age at death was 67.9 years and the average length of survival from 1971 was 13.9 years. Although the cohort as a whole had no excess mortality for any specific cause of death--including non-Hodgkin's lymphoma--significant dose-response relationships were noted between risk of non-Hodgkin's lymphoma and acres sprayed with herbicides in 1970, as well as with dollars spent in 1970 on fuel and oil for farm purposes (1).