Suicide in Australian pesticide-exposed workers.

BACKGROUND Epidemiological research has observed that workers with exposure to anticholinesterase pesticides, and particularly those with a history of acute overexposure, may be at increased risk of depression. However, there is little published research about the risk of suicide in relation to pesticide exposure. AIMS To investigate risk of suicide in relation to metrics of pesticide exposure and type of work. METHODS A nested case-control study was performed within a retrospective cohort study of pesticide-exposed workers from various industries. Ninety male suicide deaths and 270 male controls were matched by age bands, state of residence and live status. Cholinesterase inhibition was determined using subject-specific biomonitoring records collected at the time of exposure. RESULTS Suicide risk was not significantly elevated in relation to exposure to any particular pesticide classes nor in relation to pesticide overexposure, confirmed by blood test. While the risk of suicide associated with a history of cholinesterase inhibition was raised, this was not significant (odds ratio = 1.90, 95% confidence interval = 0.73-4.93). CONCLUSIONS This study did not find an elevated suicide risk associated with use of any major class of pesticide and there was little evidence that overexposure was associated with increased risk of suicide. A non-significant association between overexposure to anticholinesterase pesticides may be consistent with previous research showing increased depression in workers with a history of cholinesterase inhibition and warrants further investigation.