Adult leukemia and farm practices: an alternative approach for assessing geographical pesticide exposure.

Many studies have attempted to show a significant relationship between leukemia and farm practices, and some of them mention the potential responsibility of pesticide exposure. In this study, a pesticide exposure index (PEI) is established for geographical units at a small scale. It measures, as accurately as possible, the exposure of the farming population to pesticides, taking into account differential practices in the treatment of different crops as well as an estimate of the time per inhabitant spent cultivating each crop. This approach was developed in southern Normandy, an area of France exhibiting strong contrasts of agricultural activities, and where the necessary agricultural surveys at a small geographical level were available. Statistically significant increasing trends between leukemia mortality of males over 15 on one hand and the PEI and the proportion of agricultural land growing cereals on the other hand were found.