Abstract
Background and aims: Several studies have found excess brain cancer in farmers despite generally lower cancer incidence. The National Institute for Occupational Safety and Health Upper Midwest Health Study previously evaluated farm pesticide exposure and glioma risk and found no increased risk for ever vs. never exposed. This analysis focuses on other farm activities to determine possible associations with risk of glioma. Methods: The study included 798 glioma cases and 1175 population-based controls, adult (18-80) nonmetropolitan residents of Iowa, Michigan, Minnesota and Wisconsin. Multiple logistic regressions controlled for farm residence, age, age group, sex, state, and education. Results: There were no strong associations between farm crops, animals, or activities and risk of glioma. Prudent practices in handling farm chemicals (washing after pesticide use, not storing pesticides in the house, applying solvents by brushing or dipping rather than spraying) were associated with decreased risk. Discussion and conclusions: No specific farm exposures or activities that we asked about were associated with increased glioma risk. Farmers’ increased risk of glioma may be due to other activities or to intrinsic rather than extrinsic factors.