Multiple myeloma and exposure to pesticides: a Canadian case-control study

The objective of this study was to investigate the putative associations of specific pesticides with multiple myeloma. A matched, population-based, case-control study was conducted among men residing in six Canadian provinces (Quebec, Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia). Data were collected on 342 multiple myelome cases and 1506 age and province of residence matched controls. Data were collected by mailed questionnaires to capture demographic characteristics, antecedent medical history, detailed lifetime occupational history, smoking history, family history of cancer, and exposure to broadly characterized pesticides at home, work, and practicing hobbies. Details of pesticide exposures were collected by telephone interview for those who reported 10 hours or more per year of exposure. Exposure to pesticides grouped into major chemical classes resulted in increased risk being detected only for carbamate insecticides [odds ratio (OR) and 95% confidence interval (CI) 1.90 (1.11, 3.27) adjusted for potential confounders]. An exposure to fungicide captan [2.35 (1.03, 5.35)] was positively associated with the incidence of multiple myeloma. While an exposure to carbaryl [1.89 (0.98, 3.67)] was associated with the incidence of multiple myelome with borderline significance. The authors further suggest that certain pesticide exposures may have a role in multiple myeloma etiology, and identify specific factors warranting investigation in other populations.