Agricultural workers exposed to high levels of pesticides and people who use them on houseplants appear to have a greater risk of developing brain tumours, suggests a study published online ahead of print in Occupational and Environmental Medicine.
The results show that all agriculture workers exposed to pesticides have a slightly elevated risk of brain tumour, but that agricultural workers exposed to the highest levels have a more than twofold greater risk.
This group are particularly likely to develop gliomas - a type of central nervous system tumour. Those in the highest quartile of pesticide exposure have a more than threefold greater risk.
Use of pesticides indoors for house plants also seemed to be associated with a more than twofold increase in the risk of brain tumour. However, the authors acknowledged that this finding warrants further research because the study did not identify what types of agents, such as fertilizers, pesticides or other chemicals, had been used in enclosed home environments.
The population-based case-control study is one of the largest to specifically examine the role of occupational and environmental exposure to pesticides in brain tumour.
It involved 221 cases of brain tumours and 442 individually matched controls enrolled between May 1999 and April 2001. Histories of occupational and environmental exposure, medical and lifestyle information were collected and a cumulative index of occupational exposure to pesticides created.
The authors say: ‘The study supports the role of pesticides in brain tumours but only for high levels of occupational exposure'.
They add that gliomas are more common in men than women and speculate that ‘the differences in occupational exposure between men and women could contribute to the difference in rates between them'.
However, they are unable to determine which types of pesticide are particularly associated with development of brain tumour because information on the use of specific pesticides in a given area is not available in France.