Bladder cancer among French farmers: does exposure to pesticides in vineyards play a part?

OBJECTIVE

To appraise the potential contribution of pesticides sprayed on vineyards to the genesis of bladder cancer among agricultural workers.

METHODS

A pesticide exposure index (PEI), based on labour time and the proportion of agricultural land used as vineyards, was constructed for 89 French geographical units (départements). The standardised mortality ratios (SMRs) for bladder cancer, as well as tobacco consumption and economic status of male farmers and farm labourers aged 35-74 in the same areas were estimated for the period 1984-6. Models were fitted to the geographical data with Poisson regressions and extra-Poisson models with geographically structured and unstructured random effects.

RESULTS

Mortality from bladder cancer among farmers was lower (but not significantly so) than within the overall population (SMR 0.96, 95% confidence interval (95% CI) 0.85-1.08), but there was a significant link with exposure to pesticides in vineyards by univariate analysis (relative risk (RR) 1.17, 95% CI 1.10-1.24) and by multivariate analysis (RR 1.14, 95% CI 1.07-1.22).

CONCLUSION

These results add some evidence to the view that pesticides in vineyards cause mortality from bladder cancer among farmers, and could explain the French south-north gradient in bladder cancer, as vineyards are mainly located in Southern France.