Agricultural exposure and risk of bladder cancer in the AGRIculture and CANcer cohort.

Purpose: Literature on agricultural activities and bladder cancer risk is scarce. However, farmers can be subjected to carcinogenic exposure (e.g. arsenic, previously used as a pesticide in France). This study aimed at assessing the role of a large range of agricultural activities and tasks on bladder cancer risk.

Methods: The study population was the AGRIculture and CANcer cohort, a large prospective cohort of individuals affiliated to the agricultural health insurance scheme (MSA) in France. Incident bladder cancers were identified by cancer registries from enrolment (2005-2007) to 2009. Data on agricultural exposure during professional lifetime (5 animals, 13 crops, specific tasks) were obtained from the enrolment questionnaire. Associations between bladder cancer and agricultural exposure were analysed using a Cox model, adjusted for gender and smoking history.

Results: Among the 148,051 farm owners and workers included in this analysis, 179 incident bladder cancers were identified. We observed an elevated risk among field-grown vegetable workers [HR 1.89, 95% CI (1.20-2.99)], with an exposure-response relationship with duration of work [≥30 years: HR 2.54, 95% CI (1.11-5.83), p-trend = 0.02], and higher risk among women [HR 3.82, 95% CI (1.58-9.25), p-interaction = 0.05]. Non-significantly increased risks were also observed in greenhouse farmers (HR = 1.95), pea sowing (HR = 1.84), rape sowing (HR = 1.64); several tasks involving pesticide use, especially seed treatment (HR = 1.24); and in activities and tasks potentially exposing to arsenic compounds via pesticide use (HR = 1.49) or re-entry tasks (HR = 1.63).

Conclusions: Our analyses raise the question of a possible link between agricultural activity, especially field-grown vegetables, and greenhouse cultivation and bladder cancer.